WTF?! My friend is acting weird?

[Anonymous]

I have a crush on my friend. He already knows since I told him in January. My exact words were: I like you. Anyway, last week while were were hugging each other, he kissed my cheek. Then yesterday I asked him why he kissed me and he said, "Why not?" I assumed it was alright to reciprocate. So today I kissed him back. And then he made a strange face. Something I can't really explain. Like he was a little baffled by my actions. Then when I got off the bus, he looked out the window and smiled and flashed me the "peace sign".

To clarify things: when he has nothing to do on the bus, he talks/jokes around with me. When someone else is talking to him, he doesn't stop and talk to me. He just listens to them. When we are with a group of friends (we all have the same friends), he tends to converse with them. But if we are alone, he will talk to me.
Monday, didn't talk to me on the bus. He was too busy listening to other people talk to him. Tuesday, no kiss. Wednesday, I kissed him. Today, no kiss. He was reading a manga. He's not a nerd.