How should this guy react?

[Rastelle]

A guy, lets call him bob, told me that he likes me and almost kissed me but didn't . Since then, he hasn't spoken to me. I've tried to speak to him but I can't in school. We both are always surrounded by friends so we can't really go up to one another to talk otherwise our mates will think there's something going on between us. The only way of contact that I have with him is via facebook so I sent him 3 different messages. They weren't long but they weren't just a couple of words either (about a paragraph altogether...) I know he's seen them as it tells me when they were last on and also when they've read it. I don't know what to do. I've asked my friends that I trusted with this secret and the only thing that they can think of is going up to him, but like said before, I can't do that. What is your opinion? Is he just not replying to me for the attention? Do you think he's being a coward? Do you think I'm being just a bit too pushy? Help!

Thanks in advance if you read all of this and answered!
And thanks for those who at least read it! Means a lot. =]