I posted this in r/dating_advice but since there are 3 million people I thought I would ask here as well. Same post word for word. Thanks in advance!

To begin, the lady I've been seeing (21F) and I (22M) started seeing each other about a month ago off a dating app, and tbh we have hit it off great. We saw each other 2 previous times before this, once as a first meeting and the next with her friends and her. Yesterday we escalated pretty fast as we had been texting *ahem* in character for a few days before seeing each other. Naturally, we got a little frisky while in public so we decided to move it to my car in a more secluded area. We didn't go all the way but we were both satisfied with what we had done and what happened. We got drinks after, I brought her home, said goodbye with a hug and kiss, and left feeling a little what I thought was confused but satisfied at the moment. Fast forward to today and I wake up and see a text from her and feel a bit uneasy. I brushed it off since I thought it was me being a bit nervous for a new job I start today so I acted as normal as I could thinking it was just a little bit of nervousness or anxiousness for my first day. My first day goes well and when I get home I text her I'm home and that I'm going to go eat. She texts me back "Hii 🥰" and I just don't want to respond. I eventually responded and a bit of that feeling goes away and I feel better. My question is, what's this feeling that I'm feeling? Is it the loss of sexual attraction? Am I feeling I underperformed when we did the almost deed? The abrupt exit of the honeymoon phase? Did we move too fast? We text often so am I just socially and mentally tired of her atm? I like her a lot so I'm worried about what I'm feeling. I'm planning to talk to her about this as well but I wanted to know what I'm feeling before talking to her about it. Thanks Reddit.