Meditation could be extremely helpful if you're willing to commit time each day - 20 to 30 minutes. It will teach you to calm your mind and body and help you take charge of your thoughts. It's not a quick fix, but you'll notice benefits after a few weeks.
Find a meditation teacher. It's very difficult to learn and develop the discipline just through reading.
Also, find a therapist who's aware of mind/body connection and can support you in this,as well as working on other issues. Reach out for support - you don't have to go it alone.