I've had many session like the one you've just described, but I have to say that when I read your post, I had that thought and this one quickly followed: "You did not waste your time or T's time. Even though you were unable to speak you were building a bond between you and T. To be able to sit in a room panicking and dissociating in front of someone takes a lot of courage and trust. T knows that, and appreciates that you were there and didn't leave despite how you were feeling."

Can you ask T to help ground you when she sees this??