BERLIN -- The smiles of last November, when the Berlin Wall fell, have been replaced with clenched-jaw anxiety on both sides of the wall. The backslapping and hugging that accompanied the opening of the wall has given way to jockeying for position.

Already West Berlin Mayor Walter Momper is scrambling to persuade the West German government in Bonn to keep up the huge subsidies that have kept the western half of Berlin afloat for years. In behind-the-scenes discussions, Momper is using the ''now more than ever'' argument to keep the money flowing.

For years, visitors have remarked on how prosperous West Berlin looks for a city that is cut off from the outside world. ''Looks'' was the key word. The appearance was at least half illusion.

The subsidy of West Berlin by the West German government over the years has amounted to more than $60 billion -- in excess of $30,000 per Berliner. Half of West Berlin's budget came from Bonn. In addition, the city offered phenomenal incentives for businesses that would place their headquarters there, with university benefits, subsidized air fares and other perks.

Now there is mumbling in Bonn about cutting off Berlin and letting it fend for itself. Predictably, Momper and other city officials would rather not.

There is a bit of personal pique going on in angry arguments between federal and city officials. Bonn likes being the capital of West Germany, but it is unsuited for the job of capital of a unified Germany. It only got the Western capital designation at the end of World War II because the premier German city, Berlin, fell 110 miles inside the Soviet-occupied zone.

An intense lobby of politicians and journalists in Bonn is upset at the prospect of having the seat of government moved to Berlin. Bonn would die almost overnight, and the people who are settled in there are lobbying against the change, which our German sources predict will be made anyway.

Optimistic West Berliners are guessing that the political unification of the city will come as early as December. In any event, the de facto unification occurs today with the full conversion of the East German currency to West German marks.

In the East, the single monetary system is causing great consternation. We talked to East Berliners waiting in lines around the city for applications to convert their bank accounts. Most were worried that they won't survive in the capitalist system of the West. They had seen the high prices in the Western stores and wondered if they will be able to afford even the basics.

Many are worried that they will not have jobs, since they worked at state-run factories that by Western standards are grossly overstaffed and underproductive.

There are the deeper fears born of pride. The East Germans are about to go from being the most successful people in the Eastern Bloc to the underclass of Germany. West Germany vies with the United States and Japan for the title of top industrialized nation. Will there be room for the poor cousins from the East?

A high school history teacher told us that she is looking forward to chucking the old Marxist textbooks, but why, she asked, should she now have to teach the evils of socialism when the truth lies somewhere in between?

On the other side of what is left of the wall, West Berliners have their own doubts. They don't need an infusion of workers from an underemployed underclass that doesn't know the meaning of ''workaholic.''

Already West Berliners have a bad case of ''relative fatigue'' from hosting their wide-eyed Eastern cousins long past the time when they were welcome. ''They have a lot to learn,'' one unwilling host complained. ''Like simple comparison shopping.'' The relative in question lined up with other East Berliners at a bakery to buy butter, none of them realizing that butter was much cheaper at a nearby supermarket.

The East Berliners are defensive about their work ethic. They told us not to underestimate the pluck it took to survive and get ahead under Communism. Just give them a chance at a decent job, and they will do the rest, they say.