I felt exactly the same after my interview - couldn’t quite tell if I aced it or did badly haha. In hindsight, I wish I expanded further on some of the examples I provided but was worried I’d waffle and not answer the question properly. Did you bring in past examples of ECs and work experience into your answers or not really?
It's difficult, right?!
So I mentioned something like "When I worked as an X at X, I did this..." but it was literally dropping my job title, the employer and what I did that's relevant to the question. It wasn't anything elaborate like a STAR thing. I just didn't feel the vibe that I needed to discuss thing super in-depth as I would in an interview at an AC for example.
I wouldn't overthink it though. Ultimately, I gauged that they just want to know you as a person so even if you hadn't mentioned much or anything about your past work experience/PoRs/ECs, I don't think it'd have been too detrimental.
Good luck!