Dude , i am just like her and trust me ... She is the victim !
She is more hurt than you are , not because you've been bad to her , just because she is very fragile because of a past parenting related emtional trauma .
When the problems in your relationship appeared your honeymoon period is over. That means you got to familiar wit each other and the passion was starting to fade .

She felt then a lack of attention and love . she started feeling really bad about herself , her self esteam got really low , she started feeling that she is a drag for you and started distancing her from you thinking that she hurt the only person that could love herand that you got sick of you and that she is awfull and you will only suffer together .

Now she rejected the pain she caused herself and went on with her life and you came back to bother her again .

Give her all the love you have if you want her to get better , never judge her , try not to correct her too much , make her compliments and little from the heart presents ... be the most romantic lover that ever existed , ecourage her to get hobbies , to find new friends to hang out with and to start loving herself and you will get an amazing grlfriend .

if you can't leave her and never talk to her again in your life , she will find someone who can !