I could really use an outside view right now.?

GF and I went out from 2/13/10 until 5/12/11, yesterday. Early on in the relationship we hung out with each other at all opportunities and it was late in the school year then early in the summer. Then senior year started and we started hanging out less because we're both in difficult classes, and have extracurricular activities. Things started to just slowly go downhill from the beginning of the school year. I have always been happy with her and liked the relationship. She has said a few times recently that she just isn't happy and that it feels like something is just wrong between us. Yesterday we finally got to talking and she mentioned that she wasn't really happy with us. We talked for a while, she said she was afraid to be herself around me sometimes because she doesn't want to annoy me, which is understandable because I know I can be really stubborn sometimes, especially when people have different opinions from me. It didn't exactly feel right at the time, and it still doesn't, but I decided we should break up. It was somewhat mutual but we were both skeptical. Right now, I'm still wondering if it was the right decision. Maybe we should give it one last try (we've argued before, just never broken up because of it before). Maybe after we both get through a few weeks of this hellish loneliness, things will get better. I sort of broke up with her because I hoped that she would have a better relationship with the next guy, because she didn't really seem content with ours anymore and hadn't for a while. I feel like I just need to talk about this to somebody. This is terrible, and I probably make little to no sense right now.