Ladymacbeth,
I find it hard to believe that someone could have flashbacks, real flashbacks of something that never happened. Every flashback I have ever had has been very real about actual memories.

Maybe these flashbacks are of things that you have chose to forget somehow because you couldn't handle them.

If you don't feel trust with your therapist you need to find a different therapist.
With PTSD, it is very important to trust the person who is trying to provide therapy, yes it is an anxiety disorder but I personally believe it comes from some kind of tramatic event, even a series of them.

Just my opinion,
Open Eyes