i did something i shouldn't have

so yeah my ex and i broke up a few weeks ago and i thought i was over her but tonight i ended up at her place again. we got drunk and she said she still wanted me back. i told her no but then we started touching each other, she took off her clothes and so did i. it felt good to be with her again even though i know its wrong. we had sex on the floor of her living room, really rough and messy. afterwards i felt terrible but couldn't stop thinking about how much i still want her. not sure if i should try to get back together or just let this go.