Crush after casual sex?

So I used a hookup app to fool around with a guy in another city while on vacation. A city I live far away from. It was fun but I also really liked him. As soon as he walked out the door I just felt sad. He was super cute and even though I didn't get very long to know him, he seemed like a very open and genuine guy. And like, he is exactly my type..I'm not going to bother him with more messages or anything crazy like that. We will never see each other again. Regardless, I never expected a little hookup to be so bittersweet. I feel like I'm gonna be dreaming about this guy for weeks. If you can't tell, hookups aren't something I do very often.Have any of you guys had a similar experience?