I did not have to my self. But one of my friends from uni, which is also one of the best physicists I know had to retake most of the subjects in his GCSE because he got very interested in breeding fish during high school and did not study a lot. The thing is that in school you have to learn a bit about everything, which is very important and useful. But in uni you’ll learn about the things you really want to learn about, sometimes they will be super interesting some other times they will be boring, but you really want to learn them, so you have a motivation to push through.
In high school this is different, and you have to remember that everything you are learning is a step in the path to finally go ahead and do whatever you want to do and whatever you find interesting.