I completely understand this feeling.
I have made it clear that spankings are for fun and not for an actual behavior that he is trying to "correct'. That then makes me upset.

I think it is just a different headspace, and I don't like being in one where I think it is truly punitive - although I was also in abusive relationships so that may be why.

Unless I am missing a greater context to this, I think he overreacted. We all need to blow off steam from time to time and you seem to be taking care of your shit. So if you want to stay up past your bed time on a sat then you earned that right. If this was a 7days a week thing then sure he should sit you down and have a talk. Maybe he just wanted in you in bed with him when we went to sleep and was disappointed when you were not so he had a little tantrum?

I agree with LaceyK. Spankings can be for behavior, when you both recognize the silliness of the crime; but not when he thinks you've truly done something wrong, and you don't.

Staying up late is fun, and often productive, and everyone has to do it occasionally. And sometimes you just can't sleep... why waste the time trying?