GCSEs, in and of themselves are not that difficult; they are rather easy. It is how the exam board expect you to revise, i.e. memorising so much you literally go into overdrive.
It is unrealistic to force someone to memorise so much subject content, and that is what makes GCSEs hard. If GCSEs were more like an undergrad, students would be less stressed, have the freedom to actually explore their own writing styles/subject interests without being confined to a curriculum, and also be able to remember more, because they won't be force fed information.
I actually miss my GCSE years; in hindsight, it's not that bad. My issue is teachers make you feel like if you are 1 mark under your target grade boundary, you are useless even though you are not.
I have one piece of information for any GCSE student
Do not let your grades define you.
Do not defeat yourself if you get a 6 instead of an 8; a 6 is perfectly acceptable, as is a 4.
Peace out.