Could I be bi-polar?

I am wonder if I may be bi-polar. All my life that I can remember I have always had anger problems, but not at one thing. Little stuff would set me off in a fit of rage, my family just wrote if off as me being just a teenager. Also I was never good in school, I was never interesed in, and what I was interesed in I would just normally forget. I always wanted to be alone, I dont ever feel comfortable in a group setting. I am now living with my girlfriend and she has noticed some of these these and brought them to my attention. Such as I get real hyper and seem real happy, talking fast and super excited, than for no reason, I get mad, angry, restless. And it seems to go on like that for weeks at a time. I have constent thoughts that people are out for me, not to kill me, but they want to see me fail, and thoughts that people are stealing from me. I always swear I hear a phone thats on viberate, going off, and I just had my hearing checked and it was great. I enjoy being in physical pain, but I do not inflict it apon myself. I have morbid thoughts about death. Dont get me wrong, I would never kill myself or kill/hurt anyone. I do however wonder what it would be like to watch someone who is hurt suffer. Or what the feeling of a bullet going thought my head would feel like, or hitting the rocks at the base of a cliff. I also have eating problems sometime. I am not over weight, but I do like to eat, and sometimes for a day or two I dont want food. Some nights I dont want to sleep, I dont feel like I need it. Sometimes I have an easy day, at work, not hard mentally or phycially and all I can think about is sleep. But when I do sleep I sleep good, I hardly wake up, and when I do I have no problem going back to sleep. I just would like to know if it sounds like I have a mental disorder and whom I seek help with?