Why Do I Feel This Way?

Quick rundown: I (m19) matched with a girl (f18) on hinge about 10 days ago I believe. What started off as slow went into pretty fast and intimate conversations on the phone, and we had only been talking about 7 days when we went on our first date. The date was amazing, I hung around her dorm building with her for a bit playing card games before we went to see prime time. And then she invited me into her dorm where we kissed eachother and held eachother for a while. I was nervous, but I really had fun. I left feeling great, the next morning I felt great. But then later that next day I had a weird hollow feeling. Like I wasn’t sure if I liked her anymore. This went away after I went out with friends, but the next day it came back again later in the day. The only way I can really describe this feeling is like there’s a deep part of me saying that I should reject her and move on. But the rest of me is saying no. She’s on my mind constantly, I always wanna hear a text from her about how she’s doing. Has anyone else ever felt this way? Is this a dopamine crash? Do I not like her? Am I pre-rejecting her so I don’t feel bad? Please let me know.