In love with my friend, who doesn't love me back.

I visited a friend from university back in his hometown recently and it was really unexpected but we had sex. The entire time I was there, he was showing me around we were kissing and holding hands. He was the perfect gentleman. During this time he kept making it clear to me that we are just friends hooking up, that we aren't a couple. He also admitted that he was planning to meet someone he had met on a dating app and talked to me about her.

But as much as I try I can't stop thinking about him and I am in love with him. I can honestly say the time that we spent together was lovely. We live in separate cities so it's difficult to see a relationship in the near future. I'm not sure what to do? Please help.