I Feel I Should Keep My Feelings Hidden

There are times when he doesn't reply very amused. As in I feel like he doesn't want to talk to me. There are times that I stop replying to him and he will send me another text, still read very unamused. I feel like I'm the only one trying and I don't want to sound childish to him, asking him why he responds so plainly. Yes right now we are distance away since I'm out of the country, but he hasn't asked to call me or a video chat. It just makes me feel like he isn't all that interested. I don't want to tell him anything because we aren't even a thing.