How to deal with rejection? 😟

I'm 21 and I have never been rejected in terms of dating before. So this is potentially going to be my first. I've only had two boyfriends, and they both went really well and simple. I liked them, they liked me back.

After my second break up I was out of the dating game for a while and now I just met this guy. We started talking for about a month now, things were progressing well at first without mixed signals. He lives 2 hours away but we go to the same university, so we will be in the same city when uni starts around 3 weeks from now.

He has come down to visit me twice, spent a few days at my place and seeing each other. But lately he's been more and more distant. Taking 9 hours to reply, but his replies are still enthusiastic. I feel like he is losing interest while I still want to get to know him better.

And although I tell myself if it doesn't work out, it doesn't, it's very hard to comprehend mixed signals and possibly rejection especially since the past relationships I've been had gone smoothly. I am honestly scared of heartbreak, I want to ask him what he wants but don't want to seem crazy since we've been talking for a month and barely see each other due to work and distance. Maybe it will be better once uni starts and things start to settle. But this is driving me crazy.

I can see myself getting obsessed and overthink a lot. I think I'm just scared. Is he just being nice? What do I do?