I did about the exact same thing as you. I had been seeing this girl for about 8 months.. we were in University together. Then we graduated in April, and we each moved home, and were about an hour apart driving.
I saw her about every weekend or so, but I was always going to her, and she never came to me. She went away on a vacation with her parents for two weeks at the end of June, and never contacted me once. That ****** me off alot, but she came back, and when I saw her, it just made me temporarily forget how angry I was. Then I asked her to do some things with me at my house in the upcoming weekends, and she kept making excuses not to come.
I just let the anger build up in me later that week, and I sent her an email at work one day. It went from being a couple that morning to be separated by the afternoon. Deep down, I really didn't want to break up, of course, I was just upset at the things she did.
I really did care for this girl, and am going through the worst time in my life right now, regretting I ever did that, and what could have been, etc.
I doubt we'll ever get back together, because she is really stubborn, but of course I still hope.
But I've had some time now to think about it, and I've learned some very important things.. maybe just remember that before sending an email, write it out, save it as a draft, and sleep on it. It won't do any damage at all sitting there in your outbox. Then in the morning, re-read it.
If only I had done that.. it's like a big fork in the road, and I took the wrong path.