Bipolar's (Or anyone else afflicted with depression) - how do you know the difference between types of depression... (See details...)

I just ended a two-month relationship with a guy that I really enjoyed being a couple with. Yeah, I know two months. Epic.

Anyway, he was really nice, but a little flakey, so I called it quits. So, I’m experiencing post-relationship blues. I was just wondering, for sake’s argument, if what I’m going through is just melancholy, or if it’s bipolar-depression? (I haven’t been on the roller-coaster of relationships in a long time, primarily because of situations like this.)

It’s just with the depressive bipolar issues, it could be months before I feel better, as opposed to just being bummed out, which should vanish much sooner. It’s just, right now I can’t decipher which it is. How soon will the blues lift? Is there a way to prevent this turning into something bigger?