Bah, pain and misery..

Why is it that I feel miserable for no reason? Why is it that every few months I have to have a hormonal shotgun blown into my head that makes me rage, sob, freak out, curl up, and wish I could die? I know I'm bipolar, but even if I'm managing my disorder I still get these debilitating episodes. It makes me feel hopeless, as if I'll never be able to work or be a reliable person, because I can't know for sure when I'll have a meltdown. Cry.