Is it possible that some of the sadness is just from being seven and not wanting to go back to school after a fun winter break? One of my seven year old twins was also very sad, in fact he had trouble sleeping the night before school started and kept crying. It was awful, really- I felt so bad for him. But for him it was about wanting to stay home and play. He doesn't like school either, anytime, because he wants to be in charge of his time.