Therapists and Psychiatrists often take numerous visits or more to actually make the diagnosis of Bipolar, and that is a good thing. I would hope your therapist advised you to do a mood chart. It often can show cycles.

It's also a good idea to have a routine physical just to make sure there isn't a physical reason for the moods.

Are you able to speak freely to your T while having your girlfriends mother sitting there? I couldn't, My husband came once with me and I sat there wondering what he would think if I said X Y or Z lol .. Just make sure you feel comfortable enough to be completely honest.

Good Luck and post here all you want, ask any questions you have.