hey man, you will realize a lot being single.
was in the same situation, i couldnt deal with the things she did before we met. thats what i always got mad with.
realize now i was just being an insecure little boy. but you learn from your mistakes.
if its ment to be she will come back, if not live you life and be a better person.
go to the gym work out, party get your mind off it. break ups suck but itll get WAY better a month or two out
but dont keep on sayin sorry, thats like your beggin her back. grab your balls and be a man. give her time