These are the things that work:
Change your number. Disconnect from her completely. There is no winning when you are in this state of mind. Desperation is seldom if ever attractive and you are very desperate.
Get into the gym, start working out. Stick to a diet and aspire to Greek god status. Boost your ego, and boost your self-esteem.
Stay close to your guy friend(s). Any guy friend will do. Be able to talk openly with him about your feelings. Get it out. Do things together. Momentum is key.
Set some realistic goals like going back to school or getting a new job. Start small.
Set some unrealistic goals. Really big goals that you cannot accomplish within your lifetime. It'll get your excited. More motivation and momentum.
Drink plenty of water. Get fishoil and take a multi-vitamin. St. John's Warts if you start falling into depression.
Take melatonin at night to get to sleep after a workout. Don't stay up and play video games, watch movies, surf the internet or waste your time in any way on the computer.
Buy some new clothes. Start to feel better about yourself.
Take yourself out to dinner by yourself. Take a book with you, anything. Just do it, you won't regret it even though it feels stupid at first.
If you do all of these things you'll blow past all this desperation and be in a much better place.
Be slow to fall into friendship; but when thou art in, continue firm and constant.