There are holidays for a week which is called Golden Week from the end of April to the beginning of May in Japan. People take trips, hang out with friends, or chill at home, and they enjoy their time. But some people who enter schools or start working for companies in April get a kind of minor depression after the Golden week. Japanese people call this depression May Disease(Gogatsu-byou).
Almost all schools and companies start in April in Japan, so people who just get into new places are not used to their new life and extremely nervous and tired. Then they take their time during the Golden Week, but they have to return to schools or companies after it, and some of the people feel depression.