Ok first of all how old are you. Second I think if she wont take you back right now you need to deal with that and try to give her her space and she will most likely come back to you.

Right now you and your girlfriend are both growing and she may be growing a little bit more than you in certain areas. I agree with the others that you need to give her space. If you keep begging her and bugging her that you need her so bad, she will more than likely get really angry and will stop talking to you all together. It is better to back off and get involved with your friends or job or anything that you really enjoy enough to keep your mind off of her for awhile.
If it is meant to be, you two will end up back together regardless of time or place. Trust that god knows what he is doing and that things will get better. Give it time and you will be where you need to be soon enough.