Sounds like you've got a plan to re-take. If you want to go to Uni check out clearing anyway, see if anything catches your eye (did you have plans for Uni?)
Try not to stress too much though, unless you've got some really specific career goal and want to define your life by it - you'll be fine.
The older I've got, the more I've realized that the grades you get don't define you. Sure, it helps with some parts of life, and makes things easier, but it's nothing you can't do later if you want.
For example, plenty of people go into university later in life, and tbh they probably get more out of it. Family issues and school problems during A-levels can really mess things up. It happens, but it's not the end of the world.
Edit And if it's just your AS, not A2 then that's plenty of time to re-take and you won't have to change plans too much! It'll be hard, but give it a shot, see how it goes.