Concealed Words

Sam and me were talking on msn about how we're so close that we don't actually tell each other what we think of each other, and he felt that this was bugging our relationship; and he had to 'brb' but asked me to write what I thought... So I did. I can't remember exactly what I put but it went along the lines of that we've known each other for four years and sometimes I struggle to come up with what to say, because we've discussed a load of stuff. I've never talked about him because I've never had anything to say. But the fact I thought recently he'd become a tiny bit withdrawn and I was worried about him.
He got back to the computer and was like 'oh gotta go bye' and I'm not sure if it's because I offended him or what, but it's eating at me. I want to know what he was going to say about me. He obviously had something to say, or he wouldn't of brought it up.
I'm really worried.