Try a mood diary (with menstrual cycle) to see if there is a pattern. Thats how I got diagnosed with PMDD, the week or so leading up to my period is horrid, with my mood going from depressed to sometimes what is very similar to a mixed state, but I never personally get manic (although I have read it is possible). The rest of the month I am stable and pretty happy. When I started getting suicidal ONLY the night before the bleeding started tipped me off that there was something more going on.

I just read an article tonight about an increase in PMS symptoms for women with BP, I will see if I can find it again. Might be of interest.