I can tell you about what it is like for me. I had a recent episode and I am not completely over it yet.

It starts as a deep depression. It gets to a point where my mind can't deal with it anymore. It sort of feels like a light switch in my head. The switch gets flicked and my mind starts racing. Unfortunately, it is racing with the depressive thoughts that I have been experiencing. It is defintely a mania. all of the symptoms are there...racing thoughts, excess energy etc. Unfortunately, there is no joy or fun, just repetitve depressing thoughts and feelings. It seems to go away fairly quickly, usually within a day or so. Then it often falls back into simple depression.

I don't know if this is what you and your therapist are talking about It is just my personal experience. I hope that this is some help for you.