Don't be afraid of receiving a bipolar disorder diagnosis, especially if you have recieved failed treatment in the past for how you feel. A correct diagnosis is the path to therapeutic success.

It's possible to experience mixed episodes, something I suspect that I experience instead of the manias and hypomanias as I have never experienced a clear case of either. Anxiety and anger can easily be part of a unipolar depression but can also be indicators of 'manic' qualities in a difficult to discern bipolar disorder. The mixed episode could explain how you feel very sexual during periods of depression or maybe it's some strange reaction in your brain resulting from the physiological effects of the depression, as though you were brain were trying to jump start other aspects of your mood.

If it means anything, my sex drive seems to be completely independent from my moods. I have felt down and sleepy lately but that doesn't change that I really want to go at it. I've felt great and happy and could feel either way, and depression doesn't seem to stop me.