What you do is stop feeling sorry for yourself, and stop worrying what others think of you.
Start doing something that makes you feel good. Hell, go to the local soup kitchen, and donate some time. Ironically, you would be surprised at the contact you can make in places like that. AND you would see that there are bigger worries in this world, and some of them you can do something about!
Almost anyone, with a flicker of drive, can make the contacts, and such to get a life.
Everyone here has offered up good advice on "dealing" with the jealousy issue. Get your act together and maybe someday she will have you back, or you will meet someone who is better for YOU...