Why am I so stressed

I realized a long time a go that if I am not prepared to teach I am going to have a bad day. But I swear I have been prepared, or at least prepared enough, and I am having terrible days. I think I am getting too good. I am spending such little time on things that I don't need to work on it and the kids have time to go crazy. Or maybe the kids don't do things because they don't think they are important.