Actually, in most US states, it is illegal to record a conversation without the consent of ALL parties involved. In fact, depending on where you live, it may be classified as a felony. I'm sure your therapist would not take legal action against you for making the recording but, legally speaking, he could. For that reason, I would strongly urge you to familiarize yourself with the laws in your jurisdiction to make sure you are not breaking them.

Aside from the legal aspects of it, it's a bit of a violation of trust & privacy to record someone without their knowledge. How would you feel if you found out that T recorded your sessions, because he wanted to listen to them later and think about whether there were things he could do differently? He might have good intentions, but I bet it would make you uncomfortable!

However, in response to your reaction to the tape, don't be too hard on yourself! Most people feel uncomfortable when they hear the sound of their own voice-- it sounds weird to us, but it doesn't sound weird to others! It's easy to be critical of yourself in retrospect-- but, in the moment, I'm sure the way you handled the session was just fine.