Did i fucked up something?

Hi guys! First time writing in here so i hope to do everything correct.

At the end of October i met this girl during a holiday.

She was in our airbnb as friend of friends and since day 1/2 she gave me signal of being into me.

Then i accepted those signal and start giving signal myself to her.

Things escalated very quickly and we literally did everything (sex included) during the holiday (1 week).

Once back to our home we decided to keep in touch and if everything had gone well getting engaged after a period.

This brings nowadays.

We are still daily chatting, and last thursday we hangout (not easy to organize cuz she is 2 car hours from where i live)

After that day i noticed in her less interest into me, less chat, less good convos...

only small talk and goodnight/goodmorning.

Sometimes she used to send cute messages and now not even them.

I tend to get attached too much quickly with girls that shows interest in me.

But in this case, seen what happened during the holiday, i thought it was for a different reason.

Maybe this pushed her a little away from me.

I feel very good with her, and now i'm afraid that i did something wrong and lose her.

What do you think should i do?

I've already wrote her to ask what is happening but i'm quite sure that her answer would not be so much positive.

Sorry for my English but i'm not native and in long wall of text i lose myself