Guy problem: What should I do next...

I have been in touch with a guy who i knew through school. We started texting each other..spent 2-3 hours each day texting about very very general stuff. Likes. dislikes, music, bands, movies, passions, travel etc. I know a lot abt the person now more that he does. Past one week he has stop replying to my messages. Sends me monosyllables in answers. One day her was not in a gud mood and refused to talk about it so i let him be. We have never spoken on the phone. I am just confused as to what happened and maybe this is all a figment of my imagination but i feel something is wrong. I don't want to ask coz it would seem like i am being too pushy. He never initiates the sms, its always a reply to mine. I am not looking for anything here but i like his views and would like to have him as a friend. Not sure how to move ahead, I feel like i am in a deadlock without actually confronting the whole situation which might just be nothing. Don't want to look stupid.