@Seed,
I hear that. I call it being 'on the brim'.
It lasted a long time for me, even though I am no combat veteran. I was an Intelligence Coordinator sitting in Central Texas throughout my enlistment in the USAF, but I had many friends in the different services who were in country or otherwise in harm's way. I think all of us grieved for those who didn't make it back.
And you never know when the grief may spring up at you. In the 1980's, well after I thought all thoughts of those killed in the war were gone, I got to see a replica of the Viet Nam Wall. A replica, not even the real thing, but guess what? As I stood there with my son, all of sadness and loss just surrounded me as if it was all new.
Bawled my eyes out that day.
Take your time. Talk to people who know what you're going through. You'll be okay.
When they interview you on your 99th birthday about your life, you will still be on the brim about those days. And that's okay.
Joe(-.-)Nation