Unopposed antidepressants definitely can trigger mania in someone who has bipolar disorder. That said, we can't diagnose you or tell you that you have BP, but your symptoms are suggestive of the possibility. Unfortunately, a therapist is limited in his/her ability to diagnose the condition, and of course cannot prescribe medications; you need a psychiatrist for that.

Ask your T for a referral so that you can be properly diagnosed and treated; you can also continue to see your T for support---talk therapy is never wasted, and some types are better than others for BP (if you do turn out to have it).

I can SO relate to those who fight this diagnosis. Even though I suspected it for years, it was still something of a shock to hear the words pronounced, "I'm diagnosing you with bipolar disorder NOS". Then again, it's sort of a relief to know there's an explanation for all the crap I've put myself, my family, and my friends through all these years.

Wishing you the best in your journey to better mental health.