My love life is such a mess! How do I fix it?

I'm taking my best guy friend to prom (he's in grade 11) . . . but I'm starting to have a crush on him! :S The thing is he was like absolutely in love with my best friend but nothing ever happened and he finally just got over her, and I have no idea if he likes me too. I overheard these girls in my cl talking and one of them was like, "I know all about you and (insert name of my prom date here)." and that likes him was all like shhh! people will hear and she looked right at me. I have no idea if they're into one another or what! :S I don't wanna ask him because it would make it obvious I like him and I don't want to ruin things between us before prom! Should I take a chance and tell him, or just let it go so I don't ruin my prom night?