Why does he seem to be ignoring me?

Ok, to make this story short……I dated a guy long distance (Dallas-Houston) for about 7 months. We went on trips to Vegas and other places together and really enjoy each other’s company…….. Well last month, he told me, everyone was referring to me as his girlfriend. He said he wasn’t ready to be in a committed relationship. (I never once assumed we were exclusive, not while I was still 300 miles away) I know that in the months prior he was really into me. His friends said they had never heard him talk about a girl the way he talked about me ect…..However, I also know feelings can change and men can lose interest, especially if he started to feel I was too clingy. I obviously have feelings for this guy. But I reluctantly agreed to be just friends. It was his idea, not mine. He said he wanted to be not “just friends” but “good friends”.

Fast forward to this month, I went to Houston to see some of my friends. I did not stay at this guy’s house this time, but him and I hung out all 3 – days I was there. We seem to still be very close, just no sex. He went to tell me good night and he kissed me on the mouth. Just a peck, but still. I don’t know very many “friends” that kiss you on the mouth. The following week I had surgery, and he was so supportive. Calling to make sure I was OK, texting me, writing on my Face Book wall ect…..( I also suspect he may have gotten jealous b/c I posted a profile pic of me & another guy. But hey he just wanted to be friends, right??)
Anyway, my main dilemma is this. Since last Thursday when he texted me. I have called him once & texted him twice. It has now been a week and I have not had a return text or a return call. Yes, he is very busy, but it doesn’t take very long to write “hi” and hit send or something……….So why all of a sudden is he ignoring me like this?? He was so sweet and caring two weeks ago, and now nothing. I made it a point to take his number out of my phone, so I don’t go over board. It’s up to him to contact me. I realize he must have lost interest, or maybe he is with someone else. But, for someone who wanted to be such good friends, why is he ignoring me??
Thanks for your input. I obviously still like this guy, and was kinda hoping he had feelings for me too, and was keeping me around to keep his options open?? But I just don’t understand the sudden change….He runs Hot-then –Cold!!!