Hangingon, I can relate to sooo much of what you say. I am very similar in that I can talk to many different people quite easily, but the moment it is about me I clam up completely.
I had a very similar experience in T this week, but with a very different outcome. I like the way your T responded to you, and let you 'be' however you were, with understanding and without pressure. It sounds as though she was so gentle and compassionate with you.
When I was struggling to talk in T this week, after a few minutes of silence I was able to say something to the effect of "I can't get the words out. They're here in my head, but I can't speak them out of my mouth." Let me just clarify here that I was wrestling with all sorts of inner demons about 'not talking', 'not trusting', 'not speaking' etc. It was PAINFUL and I was working really HARD at trying to talk.
Unfortunately her response was to laugh and say "Oh well, don't mind me - I'll just sit here and think about what to have for dinner then." Then she physically turned in her chair and stared out the window.
Let's just say that I gave up trying to trust or speak and didn't bother trying to tell her anything anymore. I think I am going to quit. We just don't seem to be able to make a connection.
It sounds like you and you T are working together with whatever you are able to bring to the session... she is willing to be with you at the place YOU are at, which is so important for the development of trust. You are doing some great work. Keep at it.