Sometimes I get so angry for no reason, just tiny things set me off. I thought it was stress but I am worried maybe I could be bi polar or depression?
See a psychiatrist. Psychiatry is the specialist which may help answer your question.
It could be. There are several things that cause this sort of response, including depression. A good psychiatric evaluation can clarify what is going on and direct you to appropriate treatment. Even if it is "just stress" there is real help out there.