Maybe he somehow didn't get your text messages? Do you have his phone #, mailing address, email...? I think you two have been close enough that you're due a direct response to "So, what's up?".
BTW, I just had a similar experience with the "Long Lost Love". He totally bailed on communication with me as soon as I told him that it seemed he was a bit cool and distant, as I was experiencing him. (And he was; this is not insecurity or nothin', nor clinging or grasping. He simply let it be known he's not into telephone or email much, and didn't seek an alternative means of communication.) So I'm feelin' ya.