I'm another Bipolar II--possibly could be your diagnosis--but, as we say, we ain't (sorry, Englishteacher) experts. It takes a frustrating amount of time to find the right drug combo--and then that has to be changed again at some point. Gee, I'm making my own self depressed!

But we all have hope--and GOOD days sometimes--and sometimes that's what we need to focus on!
Also, you might consider mentioning this possibility to your therapist. I went through years of intensive therapy--now more "supportive therapy"--but therapy is hard work and if done right, it does bring up issues that can be painful and distressing--but your therapist is there for support. Just keep the therapist informed about what is happening with you, is what I recommend.
Even "normal" people have ups and downs--ours are just more exaggerated, thus even tougher to deal with.
You are definitely not alone!