Side effect of holiday?

Both Yaya and Peter are having some problems. Yaya cried this morning at drop-off. It was quite usual and I was told later that it lasted for almost half an hour. yaya said tonight that she was worried that she would be the last one in the room at the end of the day, since mommy said that it is not possible for an early pick-up. I am a little relieved if this is the real reason. I should have explained more clearly this morning to her. No early pick-up means normal pick-up around 5pm, definitely not late pick-up. During all the past couple of weeks, i thought she has got used to heading home around 3:30pm.But it turned out that she was worrying that i would not come until 6:15pm. Anyway, we will see how's tomorrow. Peter, on the other hand, has been having rough afternoons during the past two days. After nap, he became grumpy. He ate very well, according to the teacher. He slept well, both at home and at school. No real temperature(~98.5F) on either day. Just crying or clingy. The odd is that he was very happy in the morning, and all of a sudden, he woke up like a completely different guy. Yesterday, he acted happy after we came home, played around until almost 8pm. Today, he acted sick, tired, whining all the time and went to bed without food around 6pm. But, what is it? Cold? Teething? I am ready to keep him home unless he rests well tonight and acts happy tomorrow. Oh, poor kids!