Cranky 2 year old

My son is normally an extremely well behaved kid. He is normally a good listener and he is super smart. For the past two days he has been pretty hard to deal with. Really fussy and not listening. Throwing fits and even hitting (which he never does). Today it got so bad that he was virtually inconsolable. My husband and I decided to put him to bed pretty early. As soon as we left him in his room he’s quieted down, not necessarily going to sleep but just laying in his bed sometimes singing or talking to himself. Is it a bad idea to put him down early even if it’s just for one night? Is he just starting terrible twos or should I be concerned about something else?