Did he just use me for sex or does he actually like me? Why is he backing off?

natalieblue7
About a week ago I hooked up with this guy from my college (from this question: www.girlsaskguys.com/.../q1214018-can-i-get-guys-perspective-on-this-hook-up-girls-advice ) I've had a crush on for few weeks. We kissed before, but this was the first time we had sex. Before anything happened I clarified to him I had no expectations and that it was just for sex. But he kept insisting he has a proper crush on me and has spent weeks wanting to get to know me better and that he just can't stop thinking about me since the first time we made out. I specifically told him so many times not to say all that if he doesn't mean it, that it can be just sex, but he kept insisting he really likes me. He said he would have spoken to me before but that when he likes someone he's really awkward and nervous even though he's usually confident with girls in clubs etc. The sex wasn't even that good tbh, but he asked me to spend the night so I did. We spent the whole night talking and cuddling, he wanted to know every little thing about me and he was just being the sweetest person possible. The next morning he told me he meant everything he said last night, he asked for my number and we made plans for all the things that we would do together and as I said he was being very sweet. And I don't know he seemed honest and like he actually liked me.
However, he didn't call me or messaged me for the next few days and I was getting properly annoyed. In case he needed some encouragement I added him on Facebook yesterday and after that he messaged me and we just had a short small talk chat, nothing special. Then I messaged him, reminding him of one of our plans, but in a very casual, non clingy way. He never replied to that and i haven't heard from him since.
So is he backing off? He didn't need to lie to me to have sex. And even if he did, why did he messaged me again but is now backing off? I really don't know what to think about this anymore.
Did he just use me for sex or does he actually like me? Why is he backing off?
3 Opinion