Two weeks ago I met a girl at a party. I'm a good looking guy in late 20s and have no problem approaching women, so one hour later we're passionately making out in my car. It turned sexual but she was on her period so couldn't take it far.

She gave me her instagram. Turns out she's a model (and also a scientist). She said she was always in relationships throughout her life, had just broken up with her bf 3 days ago, and it was the first time she hooked up with a random man at a party.

We kept talking and met at the next opportunity. It was for a short time but we made out again. She literally couldn't keep her hands off of me and was very passionate during kissing. She talked about taking things to the next step, but she had to finish a project and would call me if she doesn't finish too late. I dropped her off to where she works, but it was already quite late. She finished around midnight so nothing happened that night. I said no worries, I could be free in the coming days.

Then she sent a long text saying that it's very nice kissing me and all but she wasn't sure about spending the night, and she had to "free herself" and didn't want to play with me.

I replied it's ok, if she doesn't want it I can't force it, but she shouldn't be worried about playing with me given that none of us were looking for something serious at the moment. She said "you're right", and ever since (about 4 days) she's been texting me way less both in frequency and content. I just matched her frequency, and then didn't text back altogether in the end. I can see that she's not online much and is visiting her family at the moment, but I know that if a woman wants to talk, she will make the effort. So it's probably a dead end now.

I'm just confused because she just went from literally jumping on me to no interest at all way too quickly without anything happening in between. What can I do better in the future to prevent this from happening?