GOT A HUGE BOY PROBLEM!!!!!!!! please helppp :[?

There's this boy that used to be in my cl, I always thought he was cute and I think he knew I thought he was cute and stuff, but at that time I still had a boyfriend. But now I'm single and that boy's not in my cl anymore. I see him only afterschool when we're crossing the street to go home. Sadies Hawkins dance just ped, and I knew he was asking around if I was going to ask him.. but I ended up not asking because we had no mutual friends and barely know each other. I didnt want it to be awkward, but lately a lot of people have been telling me he knows I used to like him... I really dont know how because I didnt like him before. But anyways, I really like him now even though I've barely talked to him. I want to make a move afterschool and start a conversation, but he's usually walking with his friend. Is it weird if i just into their conversation to say hi? Also, Everytime he sees me he acts like he doesnt know me. Is this guy just playing me or what???