On the eve of peace with Israel, Egypt is not a jubilant country.

High hopes are tempered by anxiety as the country enters a period of economic uncertainty and political isolation brought on by the refusal of other Arab leaders to accept what President Anwar Sadat has done.

The Egyptians are xpecting at least several months of furious denunciation and possible economic sanctions. Government officials say they have received assurances that military and economic assistance from Saudi Arabia will continue, no matter what sanctions may be called for by the other Arabs, but there is no indication that the Saudis are prepared to give Sadat the political support that would induce other Arab countries to follow where he has led.

Sadat's peace policy enjoys the support of the vast majority of the 40 million Egyptians. They have watched their country deteriorate as they fought four wars with Israel in thirty years and now they are ready for peace. While there are no mass celebrations, there is no visible tension as the country goes peacefully about its normal pursuits -- which this weekend are dominated by Egyptian Mother's Day and a match between two soccer powers.

Nevertheless, there are risks for Sadat in the popular expectation that peace will bring prosperity and in the malaise felt by many Egyptians over the loss of leadership in the Arab world. Now facing the reality of peace, many Egyptians seem troubled by a less than perfect deal that still leaves much unsettled and cuts them off from their Arab brothers.

Relief at the arrival of peace is accompanied by doubts about whether ti can really work and about whether the country can meet the demands for economic gain that the people have come to expect.

"The majority of Egyptians are in favor of the treaty, but they are lukewarm," said a prominent cultural critic in a typical comment. "They are not dancing in the streets, and that's a sign of political maturity because they see the problems, too. They're like me -- I accept it, with a heavy heart, not because it's a good solution but because it's the only solution."

The electric response to Sadat's trip to Jerusalem in November 1977 has been dissipated by months of haggling, by the constant shifting of fortunes in the negotiations, by a general understanding that the struggle with Israel was over whether a treaty was signed or not and by resentment of Israeli bargaining tactics.

During those months, while the government improved its economic position on paper to the point where it could probably shrug off whatever sanctions the other Arabs impose, the gap between housing supply and demand, between food production and consumption has continued to grow and public services are still deterioriating.

"If this agreement had been signed right after Sadat went to Jerusalem, as he expected, it would have meant much more," said Mansour Hassand, spokesman of Sadat's ruling National Democratic Party. "Now it's going to be much more difficult to rally Arab support for a comprehensive Middle East peace."

At home, he said, "going into a state of peace will not automatically yield evident material fruits quickly enough to satisfy popular expectations," and the government will have to deal with this frustration politically because it lacks the means to do so economically for some years.

Arab foreign and economic ministers are to convene in Agdad, Iraq, on Tuesday, after the Geyptian-Isreali treaty is signed, to decide what to do about Sadat's action. They are expected to call for implementation of the economic boycott of Egypt reportedly agreed to at an Arab summit conference in Baghdad last October after the Camp David agreements.

Unless Saudi Arabia cancels all its aid, however -- which is viewed here as unlikely -- it appears that there is little the other Arabs can actually do to harm Egypt.

Only about 7 percent of Egypt's international trade is with other Arab countries, and much of that is with friendly, supportive Sudan.

In addition, most of Egypt's sources of precious foreign currency earnings -- the Suez Canal, tourism, oil, cotton -- are exploited independently of the other Arabs.

One big component, estimated at $1.2 billion or 29 percent of all hard-currency earnings last year, is the remittances sent home by Egyptian workers in other Arab countries. Loss of that would be a serious economic blow and the sudden return of all those workers would be disruptive here, but the Egyptians seem confident that the other countries cannot do without the Egyptians who staff their schools, hospitals, insurance companies, banks and hotels.

"What can they do to us?" a prominent official here asked about the other Arabs. "Hijack one of our planes, firebomb some of our consulates? It's not a problem."

As for Saudi aid both the amount of it and the extent of Egypt's dependence have been diminishing over the past two years. But Egypt is dependent on Saudi Arabia to finance the military purchases needed to rebuild the armed forces and to keep the officer corps happy.

Figures on the actual amount of Saudi aid to Egypt vary widely. According to Ibrahim Nafie, economics editor of the Cairo newspaper Al Ahram, aid from all Arab countries including Saudi Arabia amounted to only 4 percent of Egypt's hard-currency income last year.

Although heavily dependent on Western aid and creditor forbearance, unable to halt inflation or balance its budget and incapable of cutting its deficit enough to satisfy the International Monetary Fund, Egypt is paying its bills on time and approaching economic equilibrium after years of desperation.

In the words of a recent U.S. Embassy report, "Egypt at the beginning of 1979, for the first time in several decades, is in a favorable position to begin economic planning for the medium to long term,"

That means, as Nafie put it recently, that the economic picture is acceptable "on paper." But the country needs more aid and investment just to keep standing still because its population is growing by a million per year, farm production is declining, the housing shortage is acute and public facilities are falling apart after three decades of neglect. It is one thing for the national treasury to approach solvency, another for the country to accumulate the capital to rebuild itself.

What Egypt hopes for now is more aid from the West and Japan and more private investment, attraced by the stability of peace, to help deal with these needs.

The betting here is that the Saudis will help keep Sadat afloat, despite their disapproval of the treaty, because they do not want a redical government installed in Egypt, they value his strategic support in the Red Sea and the Horn of Africa, and they want to keep their close U.S. connections. Furthermore, many prominent Arabs, reportedly including Saudi Crown Prince Fahd, have invested intourism and agricultural projects in Egypt and want to see them prosper.

Lack of Saudi political support over the treaty, however, could leave Sadat in an uncomfortable position. He needs some cooperation from Jordan and the Palestinians if his claim to have negotiated an acceptable deal over the occupied territories is to have any credibility, and unless the Saudis prod them along he is unlikely to get their help.

Informed Eguptians foresee a situation in six months or so in which no Palestinians have joined the autonomy negotiations, the Israelis are yielding little on their own, and new Jewish settlements are going up in the West Bank.

The Egyptians claim to be in regular secret contacts with some Palestinians about joining the negotiantions, but in public their program for dealing with this seems to be to hope for the best and to count on the Americans to pry enough out of Isreal to make it worthwhile for the Palestinians and Jordan to sign on.

Sadat needs to be able to show that he is achieving for the Palestinians what party spokesman Mansour Hassan called "the natural fruits of the peace process." If that happens, he said, "ultimately, reality will impose itself and the time will come when the majority of the Arab states will move closer to our political line."

Whether that objective can be achieved without at least the tacit support of the Saudis, and whether Israel will ever be persuaded to yield enough to vindicate Sadat, are the big questions hanging like clouds over the long-awaited peace.