Think of the abrupt changes; from hyper danger to killing boredom! You're like an emotional member of the 300 degree club! http://antarcticnet.tripod.com/300club.html

I would desperately try to find something in the middle distance? Concentrate on when you can get out and what you might like to do; learn to daydream again, for real. Have you a college degree? Could you work with an online college like UMUC http://www.umuc.edu/military/ that caters to military members and help yourself retrain your focus?