<human>: We started talking almost 3 weeks ago and things immediately took off. Chemistry has been amazing from the start and things have moved at a pretty good clip. She is everything I'm looking for in someone and it's been pretty magical up to this point for both of us. After 4 dates we decided to become exclusive and on the 5th date she decided to stay the night. 

While talking that night she mentioned a pet name she wanted to start calling me. It was very thoughtful and endearing but I immediately shot it down because I thought it was a little weird (both the name and the need for pet names after only 5 dates). She became really upset and left. 

Since then I've given her a pretty authentic apology but she has reacted in a way that sets off alerts for me. She has talked about slowing things down to the point of "taking it one day at a time". She's making it out like we need to get to know eachother a lot more before talking about where things go from here. I WOULD abosolutely agree with that (and did), but I have a gut feeling that's not what is really going on. 

We used to text throughout the day and for the past few days she has barely talked with me. When we have, the way we speak has totally changed. The spark is just completely gone, and her responses are short and pretty unemotional. I thought maybe I just needed to give her space and patience, but I'm smart enough to read the signs when they are there.

I'm not asking for moral back up. I know it was pretty crappy to refuse to be called by a pet name, even when she stated how much thought she had put into it. I'm asking for advice on where to go from here. Should I talk with her? What do I say? Do I end things first? Or do I just sit this one out and see how it unfolds?

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: I acted unthoughtfully when things were moving too fast. She was insulted. Things have changed for the worse, and I want to know what to do next.