What was going on when I was born?

Prime Minister Margaret Thatcher of Britain conferred separately today with President Reagan and President Francois Mitterrand of France and received what British officials said was staunch support for British military actions and plans in the Falkland Islands. ''The Prime Minister, after both meetings, felt even more reassured than she was before,'' said Foreign Secretary Francis Pym this evening. He added that both Mr. Reagan and Mr. Mitterrand agreed that it remained up to Argentina to forestall a potentially bloody British assault on Stanley, the capital, by agreeing to remove its forces from the islands. ''We are on the island to repossess if the Argentines do not withdraw,'' Mr. Pym said.

The unemployment rate rose one-tenth of a percentage point in May, to 9.5 percent of the labor force, the Labor Department reported today. It was the second straight month of high unemployment rates not seen since 1941, when the level was 9.9 percent for the year. The May rise was smaller than the sharp increase of four-tenths of a percentage point in April, however, and the number of employed workers increased for the first time since January. Those holding jobs in May rose by 780,000 to a total of 100,117,000.

Waves of Israeli jets struck at Palestinian guerrilla camps here and in southern Lebanon today in what the Israeli command described as retaliation for the shooting of the Israeli Ambassador to Britain. For two hours, Israeli planes bombed crowded Palestinian guerrilla camps in Beirut's southern suburbs. Then Israeli jets attacked southern guerrilla strongholds in the terraced hillsides around Nabatiye, Arab Selim and Wadi al-Akhadar, about 10 miles north of the Israeli border. Lebanese Government security sources said at least 45 people were killed and more than 150 wounded in the Israeli strikes here and in southern Lebanon.

In the grand setting of former French royalty, the leaders of seven industrial nations formally opened their economic summit conference tonight, still at odds over measures to ease the world recession and stabilize the value of their currencies. At their first gathering, they set aside their discussion of the world recession, however, to confer on the future of the Falkland Islands - without urging Britain to pause before a final assault on Stanley, the capital. An official close to the conference said that none of the leaders had told Prime Minister Margaret Thatcher of Britain to refrain from the final assault. The finance ministers of the seven countries, meeting at the same time as the heads of government, were reported to have narrowed the gap on such key issues as a tougher credit strategy toward the Soviet Union and closer monetary cooperation to reduce currency fluctuations.

President Hosni Mubarak of Egypt has turned down an informal American suggestion that he meet later this month in Washington with President Reagan and Prime Minister Menachem Begin of Israel, Administration officials said today. The purpose of the meeting, they said, would have been to give new impetus to the stalemated negotiations on Palestinian self-rule. Instead, Egyptian officials informed the United States that they would prefer to keep initial discussions at a lower level and would send Foreign Minister Kamal Hassan Ali to Washington on June 12 for talks with American officials. Mr. Ali went to Israel this week to confer with Mr. Begin and Foreign Minister Yitzhak Shamir. Looking for a dramatic way of reviving the negotiations on granting self-rule to the Palestinians in the West Bank and Gaza, the Reagan Administration proposed taking advantage of Mr. Begin's planned trip to the United States in connection with the special United Nations General Assembly session on disarmament and arranging a three-way meeting.

Part of each of New York City's seven beaches will be closed this weekend because the city cannot afford to hire 200 lifeguards and maintenance workers, Parks Commissioner Gordon J. Davis said yesterday. The beach closings - up to half of each beach will be affected - are the first visible effect of the hiring freeze ordered by Mayor Koch on Thursday. Mr. Koch directed all municipal agencies to halt planned hirings, promotions and merit raises immediately because of continuing uncertainty over whether the State Legislature would approve his request for $519 million in aid and taxing authority. He said the freeze, if continued for a full year, would reduce the city workforce of 190,000 by about 7,700 positions and would save $70 million.

The Government announced plans today to advise doctors and parents against using aspirin to treat children's chicken pox or flu-like symptoms because studies have linked aspirin to Reye's Syndrome, a rare but often fatal children's disease. Richard S. Schweiker, Secretary of Health and Human Services, said he had directed the Surgeon General of the United States, Dr. C. Everett Koop, to issue the advisory and had also requested the Food and Drug Administration to require manufacturers of children's aspirin to put warning labels on their products and to conduct an appropriate educational campaign aimed at doctors, pharmacists and parents. Reye's Syndrome, first recognized about 19 years ago, generally strikes children 5 to 16 years old and has a 25 percent mortality rate. It is characterized by the sudden onset of fever and severe headaches and may progress rapidly to convulsions and coma. The syndrome affects 600 to 1,200 children a year, depending on the severity of the flu season, according to the Centers for Disease Control in Atlanta.

Iran today demanded $150 billion from Iraq and the trial of the Iraqi President, Saddam Hussein, as its two main conditions for ending the 20-month-old Persian Gulf war, the Iranian press agency reported. It reported that Iran's President, Hojatolislam Ali Khamenei, said at a prayer rally today in Teheran that Iran was not belligerent and was seeking only to achieve its ''due rights in the war now nearing its end.'' ''Iran wants Saddam to be tried for the crimes he has perpetrated and Iran wants $150 billion in war remuneration,'' he said.

Prime Minister Indira Gandhi has ordered an investigation into the murder of a senior Kuwaiti diplomat who was shot and killed at his home here today by an unidentified gunman.

Scores of children and adolescents of mixed American and Vietnamese parentage were camped outside the Cuu Long Hotel today to sell peanuts to a party of visiting Vietnam War veterans from the United States and some American reporters. They also begged, posed for photographs, laughed if the visitors smiled, stared somberly, and occasionally scattered when a khaki-clad policeman or some other government agent stabbed his finger down the boulevard and told them to go away. There are uncounted thousands of the offspring of American fathers and Vietnamese mothers in Vietnam. Most live in Ho Chi Minh City. About 70 such children have been declared by the State Department to be United States citizens, able to pick up their passports at any consulate. Yet none of the 70, none of about 500 others whose American paternity has been established, and none who have appealed over the past two years to Vietnamese and American authorities, have actually left Vietnam.

Sophia Loren left the women's prison here early today, freed under a court order after serving 17 days of a 30-day jail sentence for tax evasion.

One passenger was killed and 42 were injured when a passenger train ran into the last car of an empty train waiting between two stations in Prague today, the official C.T.K. press agency said.