I've been praying vehemently to God for a miracle, that she will call and take me back and which every passing day it doesn't happen I begin to wonder if God really exists and if he does, if he really hears my prayer .
What you're doing, spiritually, is kicking the vending machine because it won't give you what you want. I understand that, but it's not prayer. It's demanding.
I am sorry you have lost your love. That's painful. Most of us have experienced that and most of us have thought we loved more than others and that we would never love again. Most of us were wrong.
I hope you find peace, and you will, if you let it happen.