Advise on what to do about a guy?

Hey so basically I have liked this guy on and off but mostly subtly on for like almost 3 years... and he's liked me too I know bc were good mates in the group and he told someone else. I sound like a 12 year old omg 😂 but he hasn't had a girlfriend this whole time right but now he went and hung out with this girl and her boyfriend and another chick who I find really damn annoying (used to be friends with her)

I'm a frigid person and haven't had a bf yet and I started 3 conversations with him like a week ago on snapchat and one of them we were up til 2am talking and he said night with a kissy face and I sent one back. This sounds pathetic but it's a huge step, but he hasn't talked to me since. Advice? I've got a class with him at school and his best mate goes out with one of mine. So I do talk to him a bit but idk wanted to see what other people like me would do? Sorry for all the writing 😂