What exactly should I do? I'm so confused...?

I like this boy name Samuel. He's been my crush since grade 6 and now we're in grade 10. In grade 6, we started dating, and I liked him because he was cute and down-to-earth. We stayed a couple for a year. And then in grade 7, he started acting like a jerk and like all the other guys who are mean to girls for no reason whatsoever. So I dumped him because I knew it was the right thing to do. But I realised I still liked him. But it was too late - he liked Avya, another girl that's super pretty, smart, nice, and funny. I tried to like another boy named Keenan, but I couldn't. In grade 8, my best friend Jennifer and his best friend Mickey started arguing because Jennifer thought she loved Mickey, but Mickey didn't like her back, so it caused a bit of an argument. Me and Samuel became close then, because we were in the same cl. In grade 9, we ignored each other the whole year - it was just so awkward, and we weren't even in the same cl. We barely saw each other. In grade 10 (which is now), we talked four times because we're still in different cles and I'm pretty sure he hates me. I just came back from school and he thought I liked Scott, another boy that's only my FRIEND. But I like Sammy, even though he's a jerk (you can't help who you like! Well, I can't). What should I do? I can't stop thinking of him, he distracts me all the time (I used to be a good student, but lately my grades have been dropping) and I don't know what to do... should I tell him I like him? I'm afraid that he won't like me back, or he'll tell his jerkx10 friend Liam who will tease me like he teases my friend Darina. I'm scared... please help.