Pushing and being over bearing

You may think that by always being there for her and watching out for her is a good thing but I found out the exact oposite. In my own attempts at thinking I was making her happy because I was always there and always watching her I pushed myself farther away. I became over protective of things she did and where she was. At the time I did not see this. Now that she said we were done she loves me but is not in love with me it was to late. I would love to have her back but knowing that I am a guy and I get jelous very fast and easy ive screwed my life up completly. When she did something I didnt like I would jump to conclusions and went back to thinking of the worst thing and accuse her before she would get a chance to explain. My stupidity costed me the best thing I had going for me. She was with me so long that I started to take it for granite and abused her friendship with out knowing it.I know its to late to ask for forgivness but I dont know what to do. I have printed off alot of the questions on this site and I have started to read them all in hopes of finding an answer in myself.