Have you tried meditation? They have tons of CD's on meditations. Find a positive mantra to try to stomp out that negative talk in your head. You can also say out loud the opposite of what you are thinking in your head. (I would recommend doing this at home )

I think ptsd or not we all have negative talk in our heads from time to time. I am sure at different extremes, but negative talk all the same.

Repeat: I am a good person, I am worthy of loving and being loved.

Sisu