Advice, HELP!?!?

There is this guy that I like, so I started talking to him. He's one of my close friends friend. After about 2 weeks of talking to him he started being who he really is and I don't like it. He acted differently when we first started talking. I'm afraid if I stop talking to him my friend will think I was playing him and I don't want that going around my school because he's liked by everyone. It would be ideal if he stopped talking to me, but he likes me so much. I will feel so bad if i break his heart. He just randomly started acting childish and rude. He doesn't act that way with anyone else. What do I do? I'm so afraid to talk to him about it. (We aren't dating yet, but everyone knows we're talking)