Leaping Jesus, I'm agreeing with snow85 here. Stay tuned for lions lying with lambs and a little child leading them.
I think that what it comes down to, Road Program, is what you're willing to put into the relationship. Yes, you're really busy, but if you actually want to have a relationship - with anyone - you've got to make some effort. In this case, the effort is little more than actually taking some time to talk with her so that she can understand the pressure you're under, the responsibilities you have, and her contribution to the entire process. Right now, she probably doesn't know what to expect, and she's reacting badly. But rather than taking a "kick her to the curb - don't kick her" approach, why not make it her call? Let her know what you need from her, and what you're willing/able to do in return. Some people can handle the responsibilities of a military spouse/girlfriend and some can't; if, knowing what's expected of her, she thinks she can handle it, she can stay, and if not, she can go.
It's not my place to say dump her or don't dump her, because obviously we're only getting one side of things. But if you really care about this girl and want her in your life, you should want to give her the opportunity to live up to the requirements of Supportive Yet Independent Military Girlfriend. If you're unwilling to do that, maybe it's a sign that you don't actually want her around after all, hmm?