Feeling under pressure when you're being pressured by your school is definitely normal! I cracked when I was in your position. I was forced into 14 GCSEs and also being bullied (which the school did nothing to remedy). In the end, I cut down to 8 GCSEs, had an abysmal year of AS levels and ran away to college to study art.
My school said, if I went to college, I'd never go to uni. The reality was, I had two years of art in a low-pressure environment, got an offer to study at Cambridge (I rejected it due to the pressure), and went on to do some other stuff.
I am now 26 and have a place to study medicine from September. Up 'til now I've had a few false starts at uni and had a few jobs. It definitely wasn't the "academically able" conveyor belt that I'd been thrust onto at a young age. In fact, for a long time I viewed myself as a total failure whose intelligence peaked at a young age!
But here I am, a relatively ancient mature student who got onto a competitive course. It is never, ever too late, even to achieve things that seem out of reach.
You're so young and mental health is vitally important. I know how bad pressure can get. Do what you need to do to stay happy and healthy. Talk to your parents. Try to ignore the school if you need to. I used to get angry when my own state secondary tried to take credit for what I saw as being "my" results, as the teaching was dire and I self-taught most of it.
You have achieved amazing things but success isn't all about grades. Getting the grades is a means to an end: doing what you're passionate about. And if you're passionate, it doesn't have to happen right now. It can wait a few years, if it's the right thing for you. Have the gap year. If you don't, you'll regret it. Take time to relax and enjoy hobbies and friends.
I have worked in the NHS for a few years and have heard dying regrets. Not one person has said that they wish they worked harder. They all wished they'd taken life a bit less seriously. Good luck.