First of all, chill. It's okay. I've just finished my GCSEs so I'm not 100% sure what universities ask for when applying, but I've never heard from anyone that they've looked at GCSE results. It's A-Levels they care about. GCSEs are just a part of getting onto the A-Level courses you want, at the college or sixth form you want. That's what you should focus on. It's wonderful that you want to do well, but don't let it consume you because you will drive yourself insane. I too set myself really high expectations and it doesn't do me any good, in fact it makes the pressure far worse. Let your drive and determination allow you to work hard over the coming years, and you will be successful. But don't stress yourself out too much, and make time for yourself. Also, don't compare yourself to your friends, thats the worst possible thing you can do. Focus on yourself and your strengths, worry about your grades and nobody else's.