I have definitely had psychosomatic reactions to therapy. I will never forget this one session, that I went in so sick, I could not speak-- I thought if I opened my mouth, I would throw up. I thought I was going to have to get up and leave the office at any moment. It happened to be a session that I knew would be particularly difficult because I had been really angry with my therapist previous to the session and I didn't want to face that-- I wasn't used to it at that point. Perhaps you can find something that soothes you or comforts you prior to the session-- deep breathing, some meditation music, etc. Have you shared this with your T?