I had always been diagnosed with Atypical Depression. Sometime in the past 2 years, my pdoc changed this to BP II, so it can happen. I don't think my illness has changed. I think my pdoc finally saw the signs and the DSM has changed.
There's a chance your therapist is just thinking out loud and is simply questioning this possibility. There is another condition referred to as cyclothymia, which is similar yet the mood swings are less dramatic than BP II.
Welcome to this forum, by the way.

You needn't have a firm diagnosis to participate here. Maybe hang out a bit, ask questions and see what you think?
As BioChe has mentioned, and I agree, make sure you final diagnosis comes from your psychiatrist, as they are best trained to diagnose.
I hope to see you around the forum.

WC