Are you on a mood stabilizer? If not, maybe that would help. I don't know if you have a SAD lamp but it did wonders for my depression. But I finally added the SAD lamp my pdoc told me to use, and it was pretty much a miracle for me. I have never been so happy/stable since I can't remember. The downside is I have to use it at least 1 hr. and daily to get the benefits. If I skimp on the time or skip a day, I really feel it.

On the other hand, if I were teaching classes as horrible as yours, I'd find myself depressed, panicked and anxious too. So it may be situational and it might just be you need out of the situation to help.