First of all wait for results day, you can't be 100% certain that you have f*cked it up until then. If it turns out you have done quite badly my best piece of advice is to retake your AS year. I know the prospect of that isn't appealing in the slightest however in the long run, your future will be more important than being a year behind your close mates. I wouldn't recommend doing your AS retakes at the same time as your A2 as they'll be twice the amount of revision. Good luck