I felt the same in year 13. I felt so pressured with all the deadlines and amount of extra work you're supposed to do. Plus, I'm the first one in my immediate family to go to uni so if I didn't get in it would be a huge disappointment. That just made me close my textbooks and waste my time on social media. I genuinely couldn't even open a textbook without getting incredibly stressed out. That feeling came and went and sometimes I was able to do hours of work in one day, but then no work for 3 days.
You just have to push through it and think of the outcome. I think I was also shocked at the level of work required of me in year 13. I'd always been getting good grades and results ever since primary school, so it was expected of me that I'll do well. I hated that pressure. Whenever I said to my dad I might not get in, he always said "of course you will you're smart it'll be easy" which really didn't help. He took me to all the open days up and down the country so he said "I've spent hundreds on petrol and hotels, you're going to uni". My mum was so much better. I knew I'd be happy in uni or not and she was happy with that. She encouraged me to work but she didn't put any pressure on me to go to uni.
I can't say it'll get easier, but it'll be worth it on results day. I ended up with A*AB plus A in EPQ. Total shock as I thought I got BCC and a B in EPQ. You can do it!