natscoolma,
I am so sorry that you had such a negative experience with the "specialist". Your description sounds horrible

I wouldn't be real eager to go back to that doctor!
Was this doctor an epileptologist? Epileptologist = A doctor who specializes in epilepsy. I presume that the feeling you're describing before a seizure hits is a "scary deja vu". Is that correct? Depersonlization and derealization both occur during a complex partial seizure. The scary deja vu is a very typical aura of complex partial seizures. There is no memory after the deja vu until we come back into awareness (usally 1-2 minutes). What happened in that 1-2 timeframe does not go into memory.
Depending upon what area you live in, there are a lot of award-winning TBI and neurological treatment centers. I go to Mayo Clinic and can't complain ~ but there are many others across the states. I don't know of any across the borders, but there are places all over the world that are well known and respected options. I'd therefore recommend looking in your area (within a few hundred miles, ideally) to begin. Talk to others that have been there for PCS, TBI, and/or epilepsy.
Gentle hugs to you ~ very best wishes!
Shez