Could I be Bi-polar?

I have been lurking on healing well for many months now and have posted in the depression section. I have suffered bouts of depression sence I was in the 9th grade, which would go on, and then off, the depression lasting as long as years, and the "being fine" lasting for between 5 months-12 months at a time. I never noticed the pattern before a short while ago when I had not been depressed in a very long time and felt myself going back to that dark place I knew there was just something wrong and it was only then that I began recoginizing a pattern. I had an unfortunate begining and I just figured that every time I would become unhappy or depressed it was triggered by something unplesant. Each time I am happy I think I will be fine, that I will never become depressed agian, and than everything will be ok, that I am free now and forever from that dark place, that I am a new person. But somehow it seems unavoidable. I have no visions or voices or frantic talking/working behaviors, and what used to be months/years of depression fallowed by a similar itme of fineness is now turning into weeks or even days of each at a time, sometimes each mod only lasting a day or two before the next comes up. Is this common with Bi-polar?. I have a friend whose mother is Bi-Polar and who needs to be hospitalized she is so bad, she talks about evil, and demands, and consperacies, and has visions, and is always doing drugs. Mental conditions are so misdiagnosed I do not even know if a doctors help will do much good and I do not want to be drugged out of my mind on 5 or 6 diffrent medications hoping something will work. I have used St. Johns Wart which seems to have a possitive fast acting effect on me but when I am feeling better it is hard to remember to force myself to continue on this, and i just feel I am ok and do not need it. Is this the start of bipolar only to get worse/ or is this soemthing else? Maybe just plain depression.

I don't think given your symptoms, that you are BP.  Unilateral depression, which is alternating between fine and depressed.

You can't be diagnosed as BP without at least one true manic episode.  Symptoms include: staying up for days at a time, needing none to very little sleep; feeling like you are superwoman, like you can do anything, inflated self image, feeling like everyone else is slow and stupid, quick to anger (rage) and extreme irritability, spending sprees with absolutely no regard for the money, promiscuity, obsessions, bursts of creativity, hearing voices, etc.

I don't think you have experienced these things, so don't worry, but definitely see someone about your depression; you don't have to live like that.