I'm afraid to say anything to him cause we already fight too much as it is...so what do I do?

My best guy friend and I generally talk all the time. We used to hang out literally 24/7 and were inseparable. If you heard the details, you would think we were dating. Well, he recently moved, and about 3months ago started dating a friend of his he's known for 6yrs. We still keep in touch a lott. Last week we texted from noon to 3am, and he called as well. The other night we were texting til 2am. Well that night, we also got into a fight over something silly. The next day he apologized (it was rather his fault moreso). I said its ok, and said it wasn't a big deal. He replied and things were fine. Well after that I texted him asking how is day is going. And he didn't reply. And today I texted him just now and he texted back. And then I said "I'm sorry if I was snippy the other night. I hope you're not mad about that". And he said "No its cool. I was just being honest and it came off harsh". And then I texted back, and again he doesn't reply. Why is he being so short with me lately?? We usually text for hours on end and this sucks. He's does this often...as he has a bad habit of being able to only focus on one thing at a time. He always comes back though. I hate to start another fight, but do should I say anything about this? And he hasn't texted me since Tuesday, which really blows...