Why does my now ex-girlfriend hate me?

My girlfriend and I have been going out on an off for the past three months. She broke up with me a few minutes ago and I don't know why. We are in a long distance relationship, but neither one of us care much about the distance and try to go on exactly like a normal couple would. She recently went into a patchy signal area and didn't text back for the day so I got a bit worried as we text or call for most of the day anyway, I figured she would be out of it by now. Ilove her and was concerned so I texted her that it was bothering me that she wasn't texting back and that I know it's not her fault and when she could text me back. Thenher attitude dramatically changed drone earlier and said quote "All you think about is yourself. Your an inconsiderate jerk. Goodbye forever." I don't think I've done anything wrong as all I care about and talk about is her, and I would lay my life on the line if it meant she could live just another day. I don't know what I did wrong so please help me figure it out. I miss her and I can't bear the thought of losing her again. My stomach starts hurting and I get headaches when we aren't "together" as a boyfriend and girlfriend. This is killing me. All comments are welcome, and please help.