This is exactly how I describe it too. I absolutely hate it with a passion. I feel powerless and trapped. Needing help and unable to get it.but when I am there something kicks in that clearly thinks otherwise.
Out of the last 15 sessions of T I had I only had one when I actually spoke any significant amount. Most involved about one sentence the whole hour.
Are you trying to speak about trauma and finding it not possible or is it about other stuff too? It does sound like you have looked at coping and self care already. It's obviously not enough when we are silenced like this so I guess we have to think what else we can do to help feel safer. I have realised that I literally have no success when I try to just force it.