I also fear you coming across as a little needy and that would chase him off.

I think we're so used to instant communication that even seconds seem like a long time.

Now, how to you stop the anxiety when you don't hear from him straight away. I would say the just keep telling yourself that that's not something that guys "need" to do straight away. Probably texting is last on a guys list of important things....
So he's not deliberately playing some game with you, he's simply playing basketball or eating. Our minds are very good at turning something simple and manageable, into a great bib tangled up mess.

Hugs.