Being needy not only sucks for you as the needy person, it also sucks to be the poor chick that you are needing. Give her a break and remember this..
She was not born into this world to please you
It sucks for BOTH of you so do something about it
Hard words to accept but you need to keep telling yourself them, the more you cope without her the less needy you will become, and the better times will be when you are with her.
The more you back off the more she will come to you, believe me I have experienced this first hand, and it is possible to build a stronger and better relationship out of the needy mess that you are in now, but you need to shift the balance of power, from her to you. If you are at her every beck and call and lose whatever life you have of your own, then you are going to be a sorry wreck of a man.
Even though it may feel like you are getting nowhere, just try to act like you are not needy, as hard as it is, you really need to step up and be the man, and if you can’t then you need to pretend that you are otherwise your relationship will be doomed.