I for one don't think if you are questioning yourself, that you are a "monster".

I come to this post from a few different directions. One, is that my husband is a Vietnam Vet and refuses to discuss his experiences there. When he returned (we were both very young), he was pretty messed up...the drugs for malaria made him ill and he was gray and weak, and his depression/adjustment was poor. After 6months of this (he improved physically once the drugs were gone) I made him go to a therapist. He went for almost 2 yrs. It helped him alot, and even though he had some difficulty verbalizing his feelings, she had him do art therapy instead. I don't see him having nightmares now, and he seems pretty stable to me. He does have a intense fear of doctors and hospitals however.

I also watch some crime shows, and sometimes CourtTV trials .
I think the "monsters" they refer to on those venues are sociopaths/psychopaths. If you Google these terms, you will see how extreme they are. There are some good books out there..One is called The Sociopath Next Door.
http://www.bookbrowse.com/reviews/in...ok_number=1530
This is a pervasive personality style, and is mostly characterized by lack of empathy for others.

So now we get to the military.... Some people in the military are sociopaths. Predominately snipers or those who can go on missions irregardless of what needs to be done. But when I was interested in sociopathy (because of a personal experience with one) and researching it , I found that the military does not really want true sociopaths in the command line. This is because they do not have the loyalty or where with all to take commands. The military experience is really difficult to many people to move on from. There is this "stress" and guilt, and conscience that many feel from combat. Some can weather it, and return to life and others can have more PTSD from it. It might be that there are physiological differences in how people manage stress.

The crime shows dwell on this trait quite a bit, and it turns up in some very heinous crimes. The Couey trial in Florida is an example. I don't want to put the details here but you can look him up. It is criminals like him and some other serial killers who are dubbed with the term, "monster". They actually HAVE to do what they do and enjoy it in a perverse way. The more suffering they cause the more satisfied they are. That is what a "monster" is to me.

Basically it is a matter of degree. So if you need to clear this up for yourself, there are new books out that explain psychopathy in detail. Dr. Hare is considered one of the best experts on this subject.
http://www.hare.org/
Without Conscience is a very good book that I have read of his.
Also Snakes in Suits discusses psychopathy in the workplace.

So the bottom line is that you may want to explore therapy, to help yourself understand your experiences better, and/or read some of the newer books on the subject. If you have lingering PTSD and nightmares, I'd seriously consider some "help".

But your post seems to me to be rather like the old expression,
"if you think you are "crazy", you are not. It is those who don't think they are "crazy" who are".