Kevin, I read this post late last night and was too tired to give you much of a reply. I am back again and reading your post because I found so much of what you describe to be significant to your question of whether you should be screened for dissociative disorder. Maybe you should send a copy of this post to your therapist.

I dont have to tell you that it is best for your therapy that you are honest about your concerns and questions.

It already sounds like you and your therapist are working on getting you more centered in the present and that is good no matter what your diagnosis is.

Take care.