Why do I think about him all the time? And him not texting back...Is that bad?

Well... He probably got distracted it happens. Sometimes we can txt a person thinking they got it but didnt. Or he could have misplace the phone or could have died or something. I don't think he's trying to be smart. Give it some time if he didnt get it txt again make sure he got it but afterward 3 or 4 times yeah I would be worried cuz he probably occupied his mine on something else. Guys are weird most of the time! Lol. don't take it too seriously though.