Back almost 20 years ago, I quit drinking, doing the AA thing. One of the things I learned was that I couldn't control my feelings, but I could control my behavior. That tied into a lot of other things I'd read and learned over the years and I believe it's still true. Living with change from what you were to what you're becoming is really challenging; you get to choose how to respond. One of the best books I ever read on behavior was "Frogs into Princes" which is sort of the bible of neurolinguistic programming. Normal is not a state; it's a range of behaviors, a range of acceptable deviancy. As a First Sergeant for almost 10 years, I had one range of behaviors; as a HR Manager for a Fortune 100 company, the range of acceptable/"normal behaviors" is a lot narrower.
I'd find a Vets Center if possible. I was fortunate enough at one point to find an Executive Coach who had been a Platoon Sergeant in the Rangers. Randy was a big help but a lot of what he did was to challenge me intellectually. First of all, there's nothing wrong with getting angry; what's wrong is to show it and do it in a dysfunctional way. If you're not getting the response you need from your actions, do something different. One definition of insanity, of course, is to keep doing the same thing while expecting a different result.
You might consider starting a blog. I write for one and use it to vent about things that get to me; I also post a lot of cartoons I like and a lot of music. Even if no one reads it except my blogging partners, I've got the benefit of getting my thoughts out there. (AW2 offers that ability for free as does http://forums.w3oc.com/index.php.) Journalling can also help a lot; the idea is to get the crap in your head out someplace where it can't hurt you. Or others. Frustration is normal; fear is normal; anger is normal. These are feelings -- by your regimental crest, I'm guessing you already know a lot of this. You just need to hear it again and apply it. One step, one minute at a time. It does get easier.
If you have no luck with a Vets Center, look for a support group for cops and firefighters as well as soldiers. We share a lot. Finally, continue to reach out like you did today. That takes courage; the courage to look at yourself and wonder how to change is really the first step. I'll be happy to stay in touch and will send my contact info along.
First it gets real, then it gets strange, then it gets different.
Warm regards,
Mike Farrell