You can't win her back right now,just follow my advice on what will get her back,which is an agreement on what previous posters said.
Move on !
Be kind to her,when you meet and then dont call her again.
Don't delete her off facebook,just unfollow her so that you don't get her updates,turn off chat from her,and delete her from anywhere else.Write her number down in a paper,and hide it somewhere,then delete it from your phone.After that,just go on with your life,doing stuff for yourself,hanging around with your mates,etc.
On the 2nd-3rd week,hopefully you would have met some girls,or just use a female friend she doesnt know,take a picture and post it on Facebook.(Sounds immature,I may get hate for that and how I actually advise someone to do something immature,but thats a really nice showoff way that your life is moving on).The girl will contact you during the first month,provided that the break up wasnt caused by a 3rd person,meaning she wasnt already moving on with someone else.When she calls you the first month,probably she will just wanna hang around to justify that maybe your life is worse than hers.On the contrary,play it cool,act as if the break up was actually a good thing,not saying that,but implying it.At the end of the meeting she will be all over you begging you to be together.Tried and tested.
And now I will you my biggest advice,since I am at your age and I kinda understand you.When something's broken,when you glue the pieces together it won't be the same...Cause that thing broke for a reason...Maybe you ll have to find someone else to have good times with
All the best mate !