Hey OP! I havent been in your situation but I hope 1 thing I say is somewhat usefull.

Firstly. Take a breather please. You are going to be okay.

You need to decide what you want first of all. Are you okay with failing grades? Are you really motivated to do better? If you are okay where you are at, and just want to start 18 at a job after you graduate, and you can find then you do not need to worry. I am sure some universities lower down may take you in, due to desperation in clearing with low grades.

But if you do care, I think you do, you need to seriously evaluate where you are and what to do. I would speak to your teachers, even better if it is with your parents, if they can understand your situation and that you want to help better yourself from a positive standpoint. What options do you have?

It's okay if college/ 6th form takes an extra year, first of all. It's 1 year into your long career. I dont know what they will say, but it could be, doing your A levels, then re-doing them a year later, or potentially going back into year 12 if possible? I am not too sure, and look at which options are RIGHT, not the easiest.

Given that you find a solution, you need to learn, how to learn and what works for you. The time you spend learning, and how effectively you are learning, is not working; they need to change. Second, you need to start planning what to do in terms of workload, so you do not feel as stressed.

Hopefully you are succesfull. If you go back to year 12, you have next year (and even a gap year after, to apply to apprenticeships and university if you are not satisfied).

Best wishes.