I am finding out, time is all that can heal the pain you feel when you are trying to get over it. That and talking to people who appreciate you, it really helps for good spirits! In the time being, just try to keep remembering that life goes on and if you arent meant to be with her, there is someone who will love and be much more special to you waiting out there somewhere for you to find her 
Keep trying to think positive and the rest will fall into place. One day, you will wake up and she will no longer be a burden to your mind. Just a memory! I hope you feel better soon. All the best
You have all the weapons you need... Now fight!