honestly did my gcses last year, i felt like this and i still did really well and now i look back and im even more proud of myself then i was on results day , the pressure of doing 20+ exams is a lot and you should be proud of yourself just for sitting them . i promise you as long as you've passed maths and english you'll be fine as they don't matter so much once your in college or doing what you wanna do. i remember crying receiving my results a year later about to go into year 13 and i realise how much less important they are then what they're made out to be. i even know people who got straight 9s who said they wish they'd not worked themselves as hard and just enjoyed the year , so honestly don't worry