Hi Little Sailor,
Your post rang a lot of bells with me. Abusive childhood, being in the military etc. I'm not totally like you, but then two human beings can never be the same. Unlike you, I often feel unbearably strong emotions of attachment to people (places and situations too). However, when things go pear-shaped - and they always do - I find I can switch them off from one day to the next and walk away as if nothing had ever happened. I've lived my whole life this way - I'm in my 70s now - and have come to accept it as normal for me. Growing old and observing the world around me has taught me there's no such thing as "normal" anyway. And at least people like us are never destroyed by regrets. While acknowledging that there are many things in my life I could have done differently - and better - I never dwell on them. I always think "if only" is the most futile expression in the English language. However, like you, I agonised over what I perceived as my abnormality when I was young.
I was treated for depression in my early 20s, and heartily endorse what Jennifer says about therapists. I saw two appalling psychiatrists, trained in the old-school Freudian tradition, who made me much worse. It took me five years to claw myself out of the even deeper depression they sent me into. However, I would say that things have changed a lot in psychiatry in the last 50 years.
I'm not sure what the military view of mental illness is these days. My only experience was a three-year short-service commission in the early 70s, and the ethos then was to keep mental health problems very much to yourself. However, that was during the paradoxically peaceful time of the Cold War, so I never saw anything remotely like action (and I was a nurse anyway). In these days, when practically everyone in our armed forces is likely to have been exposed to the stress of combat situations, I suspect this may have changed. But you'd know best.
Help of a kind came 25 years ago, when by sheer serendipity I got involved in a research programme that was looking for adult "survivors" of autistic spectrum disorders who'd managed to adapt and live under cover, as it were. (Dr. Asperger published his paper in 1944 - the year of my birth - but no one took any notice of it till the 1980s.) I got a diagnosis of probable Asperger's syndrome, which didn't help in any practical way, but at least gave me a vocabulary for my strange attitude to the world, and the possibility of contacting others like me. Up till then I'd been convinced I was in a minority of one. After this I started the long process of growing into who I was.
I'm not suggesting for a moment that you have an autistic spectrum disorder. And in any case, you can't get diagnosed on a forum, as I'm sure you realise. I'm just opening up the possibilities a bit.
Another point where I'm in agreement with Jennifer is the urge for a child. This is built in to most women (and a lot of men too) and I suffered very badly from the "baby ache" as a young woman. In the mid-70s (my early 30s) and shortly after leaving the army, I fetched up in a country where single motherhood was much easier than it was at that time in the UK. This got me to thinking about having a baby, even though I'd worked out by that time that I was unlikely to be able to sustain a permanent relationship with a man. In the end I came to the same conclusions as Jennifer, and I'm glad about that now. I don't think I would have made a good parent anyway.
Now, having passed my biblical three-score years and ten, and having managed so far to remain in rude health, I sometimes look back over my life and realise it doesn't amount to a hill of beans. And that doesn't worry me either, of course. However, in the last ten years I've started realising I need to do something to repay the Universe. Having failed to do everything I could for my mother during her long years of dementia (though I know I did more than many others in the same position) I now take care of a friend, only slightly older than myself, who has the same terrible condition. I also work as a volunteer on a crisis line, where my lack of emotion is actually an advantage. I never lose my cool when listening either to stories of terrible distress or to the inevitable torrents of abuse from mentally ill callers, and am always able to call on the techniques I learned during my training. The difficult calls are the very occasional ones from people just like myself, but who haven't yet figured out a modus operandi for coping with life. That's when the silent tears start - for them and for my younger self. I yearn to tell them everything I've just told you, to reassure them that it will be all right, but I have to stay within the confines of my role.
I hope this doesn't sound too bleak. And in any case, it might well be that you'll be able to get the help I couldn't. But you shouldn't get hold of the idea that there's some kind of "cure" out there for the way you are. Therapy and anti-depressants are worth a try, as they might help (though they didn't help me) but you're always going to be you. Reading between the lines of your post, I can see that you're already well aware of that. At heart, you are a very strong woman and a survivor, in spite of - or maybe even because of - your weaknesses. It takes one to know one!
I believe that whatever route you choose, you will eventually come through the tunnel and have a happy life, even if it's not the one you envisage now. Sometimes all that's needed to plant the seeds of change is to accept ourselves as we are, rather than always measuring ourselves against society's yardstick.