Most Helpful Girl
If you really miss HER and not just the idea of having a girlfriend, I would say that no matter how bad it ended - give it some time to heal yourself first.
You cannot get back together if you are still emotional over it. Take this time to work on things in your life that need improvement. Take up a new hobby, work out, set some goals and tackle them, read personal development books - GROW yourself first. But do all of this while keeping no contact with her.
Then when you are ready (and you will know this because you will feel nothing except happiness, even when you think about her) you can go ahead and contact her and see if you can try again.
In my opinion - only then will you actually have a shot and having a healthy and happy relationship. But you have to be strong and allow yourself to move past this first.