Adding to my above post:
My previous T and I did continue to do EMDR on a limited basis. The process revealed several of my parts. Eventually she encouraged me to seek out another therapist specializing in dissociative disorders. I did, and I am so glad that I did. My new T is working on getting to know all of us, teaching grounding techniques, developing trust, and increasing communication and cooperation in the system. We actually look forward to our sessions, and I've been told I am much more stable and happy.
There were some warning signs in the beginning that pointed to a dissociative disorder and should have been an indication that EMDR was not appropriate for me. First, and I mean right from the first session, I was unable to construct a mental "safe place." The effort produced something like a panic attack. (Looking back I was experiencing the emergence of a frightened child part.) Eventualy I was able to, but it took a great deal of work outside of session. Second, my dissociative symptoms skyrocketed post-session. I mentioned flashbacks, and there was also that feeling of being unreal, staring off into space for up to hours at a time, times when I was suddenly unable to speak or think about a topic I was just focusing on, feeling like I was sitting far back inside my head, unexplained body pains and what seemed like random emotions, and more. Also, during sessions I would experience a great deal of looping and dead ends. It was like at the end of each pass I would end up at the same thought or image over and over again. There was one in particular that would show up, and later I figured out this was a protector part that was surfacing to block the association of a group of trauma memories. Thank God too, because I certainly wasn't ready for those and I know I'm still not.