Hmm I sat some last year and I’m taking some this year.
To me it sounds as if you’re having one of two things:
1) A delayed reaction. You’ll be like you are now for another few weeks and then you’ll start to panic. I’d say watch out with this, because you don’t want it to be too late. Even though you’re chill, still start preparing with enough time in advance.
2) You’re genuinely just one of the lucky ones who doesn’t let this awful system get to them. And, for your sake, I genuinely hope it’s the latter!
Don’t worry about what’s normal and what’s not. In any event, everyone interprets and responds to exams differently. It’s a good thing that you’re calm. You’ll probably be more receptive to learning and do better ultimately, and GCSEs aren’t always the be all and end all!
All the best.