So basically I had sex with a guy in my class and I don't know what to do.

It all started back in September, we have gone to the same school for almost three yeara but have not gotten to know each other until this year in September since I switched to his class. At first "Oliver" was shy around me and did not say much, it took a while until he felt comfortable around me, afterwards we became pretty good friends him and I, and we texted a lot and spoke often.
After a while I started to get feelings for him but Oliver had a girlfriend at that time so I started to go out with other guys to ignore my feelings towards him, and it actually worked very well. When Oliver broke up with hia girlfriend I did not even think much of it since I had a small minor crush on this one guy in our school called "Harry", and I was over Oliver and I told him all about Harry.

But then came that one day that changed everything, in the past weeks Oliver had been extra sweet and complimenting me a lot, and I had mistaken his actions for kindness not flirtation. And at that week we had our class party at a nightclub since we are graduating this summer. That I had expected Harry to show up and he never did so I got very drunk, and so did Oliver who came up to me and told me to save a dance for him. Eventually we danced and he kissed me. It felt so right too, it did not feel like any kiss I had before. At the end of the night an intoxicated Oliver asks me to sleep over and I unhesitantly say yes! We arrived at his place, we ended up having sex, sex with him felt like no other and was amazing. We frel asleep cuddling afterwards. When we woke up we had school and we were both hungover and a mess so I did not think much of it until the day after when it all came back to me, and I just felt confused about it. I did not regret it at all I just wanted more of it. More of him. When I went school again he acted the same to me like nothing had happened. He still talks to me a lot. And sometimes it feels like it was a one off thing and that ehe wants to sleep around, and is not searchig for a relationship since he broke up with his ex a few months ago, but he is so sweet and kind, and still is and hugs me more which makes me wonder. I don't what to do and I am too scared to talk to him about it all. I just need to know how he is feeling about it all.

There are danger alarms ringing all over the place here. Since this was posted in the Teens forum, I'm assuming you are still in High School. So you are drinking underage, And not just an occasional drink, but enough to get drunk. The second danger is that you had sex and apparently not for the first time.

So I see a picture of a teenager who drinks and is sexually active. A recipe for disaster.

So the answer to your question is to wise up and start changing your behavior patterns.

If you want to know what to do about Oliver, that is to sit down with him and be totally honest.

A couple of things confuse me here
1-class party at a night club
2-graduating this summer
3-arrived at his place (his own or his parents)
Are you guys in high school?
If so then for starters you could have avoided this by staying sober. Are you even legal drinking age?

But to answer you question you won't know how he feels about it unless you ask him.
If he doesn't want to talk about it then you can't make him.
In that same respect if he does not want a relationship at this time, then you can't force that either.
Basically what has happened is you two got drunk, you got disappointed by Harry not showing up and fell into what felt good at the moment, and probably messed up a good friendship in the process.
You dated others and forgot your feelings for him before, you may have to do that again.