How come he stopped texting me?

This guy texted me about a month ago and he was really sweet and we got on well but about 2 weeks ago he just stopped texting me, we see eachother in school but we aren't in the same class, and before u say it's because he's waiting for me to text him it's not that, there was plenty of times in the last month that I texted him first, so what do you think it is?