I'm broken HELP!!'

I broke up with my girlfriend 3 days ago now because she admitted to flirting with other folks last time she told me she was flirting with other dudes I said "please don't do it again" she promised me she won't and said I'll get your trust back I promise. 2 days ago I asked her if she still was, she said no I asked her to swear to god she said she can't because she still flirts with those guys she didn't even say sorry I asked her if she was happy with the results and she said she dosnt know what to say I didn't get angry or say anything nasty I simply told her I want to break up and I did.

My problem is I love her so much that I wake up and all I think about is her sleep she's in my head nothing else she's always active on Facebook? I check my phone rapidly waiting for a call from her or a message but I know I'm just contradicting myself.

What do I do?