I did 13 years in the service, and it had a great deal to do with the type of person that I am today.  The experience ages us and gives us a depth of character that only those who have sacrificed so much can truly understand.  I believe that this is one of the reasons that veterans share so much mutual respect and understanding amongst themselves.  Outside of this BBS, I've never had a single person thank me for my service.  Never.  Aside from some meaningless decorations, I never got a thank you from the military either.  You may never either.  They decided that since I was getting out, there was no point in doing any extra paperwork on me. It doesn't matter.  We KNOW we didn't do these things to receive anyone's gratitude anyway.
Once I became a civilian, it took a loooooooong time for me to de-program my brain from military thinking and perspectives.  I've been out since 1991, and as recently as 2 years ago, I was informed by a girlfriend that it was OBVIOUS that I was a military man.  That relationship didn't last.
You're right, it's a world that only those who have been there could understand.  In the civilian life, this can make us feel very lonely at times.
I tried to stay in contact with my "bretheren" for years, just to have people in my life who could relate to that part of me, so I wouldn't feel so alone with my thoughts and memories.
I urge/suggest joining a good veterans group, rather than trying to suppress all those emotions.  You aren't alone, but sometimes it DOES feel that way.  We've got a lot of people around here who DO understand where you are at.  There is nothing finer than a bunch of good guys supporting eachother as they all tackle the same issues.
It's been so many years now, but I still, frequently, have dreams that I am back in the service.  Some are nitemares, and some are good ones. 
Sometimes I wake up wishing I was back overseas doing those things again.  Sometimes I even get romantic about it all, and really get to missing people and places.
I expect that it will always be like this.  I have learned to accept it.  I carry my service with pride.  Not so much pride in my country, but a satisfaction about who I have become as a person.  Here's a BamBamism for ya:  "I'm not who I am because of what I have done.  I am who I am because of what this has done to me."  
I am "okay" with "me."  I did what I believed in at the time, and did plenty of extra too! I did it well.  That's all this man needs to know to be "okay."
A couple of weeks ago, the "unemployment office" called with a job in Bagdad for me.  I almost jumped out of my chair and ran down there.  For some strange reason (not the $90,000 a year) I felt that doing this job would somehow make me feel "whole" or "complete" again - like my life becoming a full circle.  I didn't even realize that I was thinking this way until many days later.  I turned it down.  I've moved on with my life now, and I've got kids right here who need a Daddy at home.  I am pleased with my choice.