Most Helpful Girl
You need to stop being so hard on yourself. It was just sex. You enjoyed it at the time and you did nothing wrong. You're not a whore or a piece of meat, and you're certainly not scum. You're a human being with needs and you scratched an itch.
If you don't wanna do it again, just be honest with him if he tries to hook up with you again - just tell him "look, that was a rebound bone and I'm just not feelin' it." But, if the sex was good and you intend to stay single a while, why not keep bonin' the dude? You already did, so that notch has already been added to your metaphorical bedpost - might as well make the most of it lol