Feeling headachey, feverish, stuffy, exhausted and downright miserable? There's a lot of that going around in the Washington area and in plenty of other places around the country.

The flu season has officially opened, according to public health officials and physicians who track influenza. No one is calling it an epidemic at this point, but at least one Virginia health official is reporting "widespread influenza activity."

Whatever the experts call it, flulike illness has taken a large toll at some classes at the Chevy Chase Baptist Church Children's Center in Northwest and has filled some local pediatricians' offices. It has doubled the number of walk-ins at the student health center at American University. And it is apparently the leading cause of increased absences at Potomac Electric Power Co. in the last 10 days, causing the company spokesman to joke, "You could say we are having an employee outage."

"The overall picture is that flu is here," said Dr. Martin Levy of the D.C. Public Health Commission. "There's a moderate amount involved right now, with more in certain pockets . . . . How much more there is still remains to be seen."

In Virginia, the picture is slightly different. Dr. Jacob Jones, the state's assistant epidemiologist who tracks such diseases, said that based on a surveillance system involving 30 physicians around the state, "influenza activity was widespread" as of last week, and five cases of influenza had been diagnosed through laboratory analysis.

In Maryland, Dr. Sam Shekar of the state Department of Health and Mental Hygiene reported 12 outbreaks of "flulike illness" in nursing homes and long-term care facilities, half of them in the Washington suburbs.

Physicians are reluctant to label an illness influenza unless it has been diagnosed through laboratory analysis. But when they have several confirmed cases and many people who display the same symptoms, health officials feel confident that the flu has struck.

The main concern of public health officials and private physicians is how to deal with the illness. Several said that people in high-risk groups, such as those over 65 and people of any age with chronic heart or lung problems, should be vaccinated.

Jones said that it typically takes about two weeks for full immunity to develop. Officials are concerned that this year's vaccine, designed to protect against the Leningrad flu, may not work as well against the Sichuan flu, the strain that now seems more prevalent nationwide, according to health officials. Still, many said, vaccination may be advisable.

Dr. Joel Taubin, an internist and pulmonary specialist in the District, said he is seeing many patients who have secondary infections that developed after the initial flulike condition. "The initial flu, fever and muscle aches are gone, but they are left with sinus or bronchial problems," Taubin said.

Though the best treatment for the initial illness is often rest, liquids and medication to ease discomfort, the secondary illnesses can and should be treated by a physician, he said. He recommended seeing a physician if the flulike condition persists for several days.

Pediatricians Ira Seiler and Thomas Sullivan, who practice in Northern Virginia, reported waiting rooms crowded with youngsters complaining of flulike symptoms. "It has been running rampant," Seiler said.

He advised parents to keep their children home if they appear to have flulike symptoms. He said he understands the difficulties of working parents, but he added, "Sending a child to school -- all that does is spread the illness."

Seiler said that if a child "is acting very sick, he should be checked out" by a physician.

Sullivan said that 60 patients -- three times the normal number -- went through his office Saturday. The numbers, he said, appear to be greater than last year, though the severity of the illness is not.

Sullivan said children should be treated with aspirin substitutes, such as Tylenol, because aspirin and influenza have been linked to a serious condition known as Reye syndrome in children. The syndrome can cause liver and brain damage.