Guys,
While I don't have it, I was a medic in the military in the 80's in a combat unit and dealt with 3 situations. First off I want to tell you that you, as you can guess, are not alone and it's not somehting abnormal about you.
Second, do NOT use mind altering chemicals. No drinking, no drugs, and you should probably quit smoking (I'm a smoker, I know that pain).
Third, find a vet group nearby. You would be amazed at how simply talking eases things. Talking on this board will help the group of you suffering, but human face to face contact is much better.
I wish you guys the best. When you notice the onset of your symptoms, stop and immediately deal with it.
Now, personal opinion without scientific basis. The mind can be trained, it's not easy. Seriously, try yoga. Getting into a daily habit and practice would help focus the mind.
I'm not belittling the things you've seen, done or experienced. Thhis is something you will live with forever. Oh and, I'm not Tom Cruise...if you need psych prescribed drugs to get you over the hump, USE EM, but correctly.