First of all, I will have to disagree with ratbastid's description of the "average 19 year old."
Second, I have to say that both of you are bringing on the drama. Your girlfriend needs to get herself a hobby besides talking to her friends with relationship problems, or else she'll go nuts wondering if her relationship has problems. You need to stop letting things get to you. If both of you act dramatic and make a big deal out of the little things, yeah- you'll break up. Try talking about all the good things that work in your relationship. Also, about the whole driving thing- she needs to understand that you can't and won't drive four hours everytime she is upset about stuff. It's just impractical.
I'm not sure if that helps at all...It was a very long post to read, and I hope I didn't skip over any real issues.