I'm pretty much in this same situation right now. Got dumped by my girlfriend of 2 years, we were both too depressed to handle our first relationship. I've had a lot of time to change things though, and even if I feel like we could really have something again, how the hell am I supposed to convey that to her? I'll just sound desperate. We really did love each other, and she says she still does, but as a friend.
I think she just needed the type of fast, open relationships with a lot of other guys that she's been going after, but holy shit it'll hurt if she starts really dating another guy. How the hell did she get over this so fucking quickly and I am the most fucked up I've ever been by far? Must have been a week and a half, maybe two, and she's already fucking other people. I know the physical things might not matter all that much, but she broke up with me for this guy. Thank fuck she never cheated, we respect each other so much that she couldn't. Here I am 6 weeks later, still haven't decided if I'm going to live or not. If I look at it one way, I want to be around for as long as I can to be here for her because I really do love her (or at least who she used to be- I'm not the only one doing some changing. Who knows if she's better or worse, but I certainly think she's the one for me. It sucks how you only realize this once it's gone)-but at the same time, if I can't have her back eventually, my life means very little to me. It'll tear me apart.
Not living for much else anyway,. Except for trying to improve myself, for her. I know people say it's a bad idea to go after her again, and I absolutely realize I'm setting myself up to get ripped apart, but people don't know how little that matters once you're in this situation. I developed as the person as I am today because of this girl and for this girl, and to me nothing else matters. I might be in a worse state of mind than I thought possible, but fuck if I'm not determined enough that it keeps me alive for now.
The story might not be inspiring or make you feel any better, but the idea is that I know exactly how you're feeling. This isn't a feeling that anyone should have, and it sure as fuck isn't one that they should have to deal with alone. If you want to talk, maybe it'll help us both. I'm try to keep myself busy and my phone is a bit spotty with message notifications, but PM me and I will make time to talk to you.
To me, the feelings don't mean much. As long as I'm going out anyway, a couple more weeks or months feeling like this, it just doesn't make a difference. Don't you go doing anything drastic without talking to me, or any of the amazing and genuine people that are going to respond to this thread.