Don't know what is happening

Ok so I like this guy and he told me he likes me. We talked ALL the time for hours everyday and now when I text him he will never reply and when he does we talk for 5 minutes and then won't reply back and I know he has read the messages bc it says that he did and I really like this guy so I'm kinda confused about what's going on. We smile at each other whenever we see each other but otherwise nothing. And don't say he's a jerk because he really is the nicest guy I've ever met and no he didn't brainwash me or anything😂 he really is nice. Thoughts?