Ever since school started, I've been slowly falling behind. I am constantly out sick. Today, I lost my calculator, got a 0 on an exam and completely freaked out at my teacher, and then began crying in the middle of the hallway. My jaw has been locking up on and off for a week, and I feel like no matter how hard I try, I cannot get to sleep on time. On top of it all, my work has been piling up, and I can't seem to force myself to do it. I don't know what to do.

I need advice at the very least.