Just read the entire thing and wow! Firstly, it depends on your ultimate goal. What grades do you need for a certain uni? Could u go through a different route with your current grades? Or can u deal with doing all these exams all at once but i certainly couldn’t. My advice is resit your a-levels and look at Uni that accept your IGCSE and sats grades. You could apply for a deferred entry? Are you confident you will get higher grades when you resit your a-levels. Yes exams are a crucial aspect to get to where you want to but don’t put all this pressure on yourself. But at the end of the day it’s your choice, if you believe you have what it takes then do it. My advice is just to resit your a levels and apply the year after. Also, good luck with your studies, believe it yourself. You can do it !!!!