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.