I can't say much, just that bipolar disorder doesn't always fit the textbook description line for line. I have it and I never went through promiscuous stages and I also never spent money wildly like some do. I would get depressed but not stay in bed like some people do and like you described your girlfriend. I can't tell you if she has bipolar disorder, though from your description, I would see why you might think so, but I can tell you that every person who has it is different and the textbook descriptions aren't always accurate in my opinion.