ARE YOU FACING A BREAKUP?
Ok so lets asses the situation. Your GF broke up with you ...
There might be 2 reason... First you were not capable enough yo give her proper love, care and understand here expectations that she had from you and you were not worthy so she moved on (sorry for the harsh words)
Second you gave her your best and she was greedy and unworthy so she chose someone else....
Whatever the reason was its done... Now what you have to do is... Cry loud as much as you can this is natural but don't stuck in past... Just move on... I am not saying its easy but its not impossible.
Thats how life goes on, its a part of the learning & growing process in life, accept it, keep your head up with a smile .. and prepare yourself for next wonderful thing coming in your way.
My best wishes are with you