Oh, and be prepared for the embarrassment and feeling stupid the first few times the therapist actually tries to help ground you. As MUE mentioned, sometimes they will tell you to feel your ground on the floor, look around the room, etc. My T started talking in this super calm, soothing voice and he was telling me where I was, and even what day of the week it was. I was like, REALLY? The day of the week it is?? How pathetic am I?? But the reality was that I HAD totally lost track of exactly where I was and WHEN I was. Knowing it was Tuesday and I was in his office at 11 am and it was 2012 actually helped yank me back to myself and the present. I felt really silly though, and then T and I talked about that. As the others have said, it is a totally normal response to trauma that we developed for a reason. We can unlearn it, but it takes time and practice.