Nathan, I have worked third shift for the last 13 years and I know it's not easy working an off shift. If your working long hours the sleep that you are getting is probably being interupted. I sleep four to six hours a day and I am very bitchey at times. The phone rings, kids yelling outside, and traffic keeps me awake. To deal with this I take a lot of naps and then my wife gets upset because all I do is sleep. So I try to spend some quality time with her each day.
I agree with the advice of everyone here. Get into Therapy, exercise, spend cuddling time with your wife, and talk to her, not about work, but about you and her. I know this sounds hard to do with working so many hours but hopefully the long hours won't last forever.
When you get ran down the emotions may flow but that can be a good thing. It helps release the build up that's inside. Know that you are not alone, know that all of us are here for you. I for one have the highest regards for you and admire you for for being able to be a survivor at such a young age. I am proud of you. You have help me so much. You have reached out to so many of us and we will be here for you.