The anxiety is often not generated by conscious thoughts. Therapists are trained to deal with thought based anxiety. With PCS, the brain is physiologically put in an anxiety condition that causes it to collect all of the thoughts that it would normally just let fly by.

I was given Klonopin and took a half dose. I don't take it any more but do have some in my 'emergency' kit. If my anxiety gets triggered unexpectedly, I can take a small dose and get settled. I rarely need it.

There are a variety of therapists and protocols for dealing with 'flight or fight' anxiety. You might ask your therapists if they have a referral.