So for context, I've already met and slept with this girl about a week prior to this interaction. The night went well, we also talked and vibed really well in person.

She wasn't looking for anything serious and neither am I but I usually don't say explicitly, I would just be vague about it i.e. it leads to whatever it leads to as I think committing to one of the other doesn't work.

I was honestly waiting for her to message me as she seemed eager in person and said she would but a week had gone by so I thought I'd send her a meme that we both get due to our current university degree courses.

The response I got seemed off like she was being difficult or that she seemed annoyed, when she wasn't like this initially it in person. I'd appreciate any advice I can with this.