Hiya 👋, I completely understand your anxiety around starting sixth form a levels. It is absolutely normal - I started year 12 in September so I can’t give you a run down of much of the course but from what I’ve done I can give you this:
I’m not going to lie, it’s not easy, but I suspect you know that - however (obviously teacher support varies from school to school) there is generally a lot of support with clinics for subject support and most teachers are available for contact most of the time. I would highly recommend websites for revision materials, they help you revise as well as covering lesson content which you are concerned you don’t know (like save my exams, physics and maths tutor, studymind etc…) course content is also covered quite thoroughly and I believe you will revisit it throughout the year to remind you.
I hope that sort of helps, any questions just drop me a note! Sophie