before the break up, you felt like a sex god. you felt desired and you thought getting a girl was nothing. when you break up with that girl. you feel like shit you feel you're nothing.
now list the ways you got over that.

you could follow Style and Mystery's method of sleeping or going out with 10 other girls to get over your ex

personally though when I went through this last summer, I just hung out with my friends and listened to good music..and they both helped

Since I got divorced a few years back, it's been a lot harder to bounce back from relationships, and I've had some real ups & downs with my confidence like you're describing. I'm going through a situation right now where the girl I was seeing just moved away, and I'm definitely fighting through that down feeling. Here's what I've found to work pretty well to get me back on course:

1) This is from Sinn's Game Acceleration guide - write down 10 reasons why a woman would be lucky to be with you. As a result of the break-up, you probably have a sub-conscious list (even if it's just one item) of why women don't want to be with you, so this helps counter it and serves to remind you that you're not just some fool. Every now and then when you have that "piece of shit" feeling, read it or just go over it in your head, and you'll feel your chest start to puff out again...

2) Get out there! Obviously, everyone says this, but the reason is because it's true. Nothing helps you forget about the last girl you were with better than hooking up with someone new. Even if it starts off simple with # closes and flirting, the faster you realize that there are other fish in the sea and that they want you, the better you'll feel. And once you get laid again, you realize that you're the man.

3) Put it in perspective. This sometimes takes a little self-philosophizing, but you really have to sit back on your own and think about how that relationship - and relationships in general - fit into the broader context of your life. Even if women are the absolute most important thing in the world to you, there are still bound to be so many other things that make you tick. Friends. Travelling. Music. Work. Education. Charity. Whatever it is, there are so many ways to channel your energy and derive positivity and confidence from them, so take the opportunity to expand yourself. For me, after I broke up with the first girl I met here in Germany, I used it as an opportunity to get back into exercise, focus on learning German, and get back into reading; this really helped my mind move past the the girl, and it also had the benefit of making me a better, more well-rounded person that would be more successful at gaming women.

Anyhow, everyone is different, but I've really been focusing on these things over the last 6 months, and it definitely has helped.