Worst Mood

I am in such a foul mood today.
I don't know why, just every little thing annoys me. I feel really over-critical of everything. I was even just listening to my iPod, criticizing the artists in my head. I nearly told a classmate off just because he was sitting in my chair, I was getting pissed off at my friend who was just trying to start conversation, etc etc.
I almost don't want to go to small groups tonight, not because I think it'll make things worse, but because that would involve being social and I don't really feel like talking to anybody right now.
Just.. such a bad mood.
I'll probably end up going to small groups anyway though, just because it's routine..