If you are in therapy, your therapist, who knows you, might know of a good distraction technique that would work for you. Or you might decide to go in the other direction, and concentrate on your breathing. When I do this, I don't try to control my breathing or my thoughts. I just watch what my belly is doing as I am breathing in and out. I also like walking meditation, repeating a phrase from Thich Nhat Hanh ("I have arrived. I am home. In the here and the now. I am solid. I am free. In the ultimate I dwell.") as I breathe as I walk. It also helps bring life meaning to do something for someone else, even a small thing. But if I were experiencing what you are, I wouldn't hesitate to call my therapist.