Hmm well, I would suggest talking to him, to see what's going on. If he's just busy, then try to find something for you to do while you wait for him to get back. People can get pretty busy sometimes, and that's the great thing about texting, you can reply when your in the middle of something, or you can leave for a bit and come back later to continue the conversation instead of having to reply immediately. Try not to be too upset when he doesn't get back, I totally relate, it can get upsetting when someone doesn't reply immediately. But that's ok, try not to be too bothered. Also, if he comes off as dry, maybe it's just because he's busy and has to be quick, he's tired, or maybe it's just because he's bothered about having to do summer school, not because he's bothered with you