Stop hanging out with her. no contact. It will only get worse if you stay in contact with her. How do I know this? I know this because I fell into the same trap and it won't get better - you will just get more and more pissed off everytime you see her. Things are never the same after a break up. My two cents.
I will do my best to reply with an educated, humble and honest answer. Ultimately, it is up to you whether you want to listen to my advice or ignore it completely. Sometimes, my advice may be wrong; occasionally, it will be right. Regardless, I want to do my best to give people answers they are seeking.