AlphaSnake = correct
You're 18, I didnt' have my first girlfriend till I was about 18... you have plenty of time to meet more women, so just throw out all your 'sentimental' stuff, delete her screenname, don't return her calls or IMs, don't bother with her, and move on. Take up a new hobby or something (videogames?), start going out more, call up and hang out with people you haven't seen in a while... It's really tough to do in theory, but once you do it, you'll be MUCH better off for it.