Just something else for you to consider - you say that you have had mental health difficulties, in particular anxiety, and that you find exams very anxiety-inducing. Have you considered how you would cope with a course like medicine? It is very intense, with a lot of exams. Basically, what I'm saying is, if you want to go for medicine then you need to have some kind of strategy in place for how you're going to tackle exams differently so that you can manage them and not find yourself too overwhelmed by anxiety. Mental health difficulties are by no means a barrier to studying medicine, and there are many medical students and doctors with mental health difficulties, and who cope with the demands and rigours of the course. However, you need to be realistic and make sure that you have a workable plan in place to make sure that what happened during your AS levels doesn't keep repeating itself in subsequent years.