Okay, so reading over the thread there are several things jumping out at me, and I've been in some similar situations myself, so might be able to give some advice.
1 - The issues with your mum. I know right now the main thing you want to do is get out of a toxic household, and I can understand that as it's something I've been trying to do for the last 3-4 years (and finally have managed). But going to uni isn't going to solve this problem. Don't go just because it's a chance to get away and start somewhere new; that's entirely the wrong reason to be going to university. Have you tried sitting down and discussing this with her, maybe getting some careers advice people to go over things with you both? As hard as it is to get away from parental expectations, you need to pay no heed to what
she wants, and do what is best for you.
2 - Work Experience. You don't know what you want to do with your life? Work experience. Look into sectors you're interested in - research, lab work, technician jobs, engineering jobs, something completely out-there - and try and get work experience in it. Try different things, see if anything clicks. You may not get paid for it, but a day or two trying out different things is a) a great way to meet new people, and b) a great way to get an
idea of what things you might be interested in. Because, as people have said, liking GCSE physics is a completely different ballpark to working in a materials research lab or doing engineering.
3 - Take some time out. It sucks. Believe me, I know. I was only there for 2-3 months of my AS Levels, after dropping 2 of them, due to illness. Then I moved college, and it still took me several attempts to get the grades I needed. But, I got them. I'm not happy it took that long, but the point is I kept at it until I got through it. If that meant taking a year-long break, I did it. If it meant swallowing humble pie and accepting that my friends will be in the last year before I even start, then so be it. It's hard, but don't get wrapped up in the timing of things. There is no maximum age for when you go to uni - there are people even on courses like medicine who decided in their 40s to have a change of career, so you undoubtedly will not be the oldest on your course while in your 20s. Other people will not give a damn, I promise. They're all too busy worrying about what they're doing with their lives to care whether you started uni at 18 or 38. That, and unis often look favourably on older applicants/mature students, as they have a lot more life experience, and have had longer to think about whether or not this is what they want to do. I've found there's a huge difference between the mindset of 18 y.o freshers, and maturer applicants: and I've picked that up just from interviews. Sometimes some time out to 'mature yourself' can do you a world of good, so that when you come back into things, you feel more confident in your decisions.
4 - Make a list of things you don't want to do. It's really hard to give any sort of careers or education advice when you haven't even said, really, what you aren't looking to do. If you don't know what you like, then surely there must be things you know you
don't want to do, be that working with children/elderly/animals, artsy jobs, office jobs etc.
5 - Is physics really for you? Echoing what others have said in this thread: you're saying you like physics based on GCSE physics, but didn't take it at A Level, and are now applying to do a foundation degree in it at uni without really having experienced anything to do with it...? I'm not trying to put you off, but it sounds more like you like the idea of studying it, rather than actually studying it. You also said earlier in your thread that you're tired of doing research stuff - not sure whether you meant researching careers etc, or doing research tasks, but if it's the latter then a science subject really isn't going to be the most fun for you, as it's a lot of independent learning and research.
If you want to do physics A Level, I would suggest looking at another sixth form or college. You really don't need A/A* in it to start at AS. If it's something you want to do, go for it!
You'll do much better at a subject if you enjoy it, I've found.
6 - Mental Health. I feel obliged to mention it any time someone is struggling during sixth form years, but have you spoken to a doctor or school counsellor about this? It's a good idea to flag up that you're feeling lost, apathetic, etc before things get too bad, as depression can be hard to shake once it has a hold. There's no shame or weakness in asking for help. I know it takes confidence, but it may well be worth your while just talking to someone about how you've been feeling. Getting it all out there and talking it through with someone may just help you see things a little clearer. Look after yourself.
7 - Forget Uni Prestige. I don't know exactly what courses you applied to, but aiming for STEM degrees with very little background in science (even a foundation degree) at top universities may be a little too much, especially when they may very well be able to pick up on the fact that you don't know what you want to do. You'll be more likely to get accepted on a course if you can show you've looked into the field, done some personal study around it etc. Which goes back to my earlier point, and something others have said, in that volunteering and work experience
is invaluable.
Going to a non-top 30 uni doesn't mean you're not going to get anywhere. Make the most of the degree, make connections where you can, and work at it.
Another thing I want to work out is: what don't you like about apprenticeships? I can understand if you have a specific career in mind, and can't do it via apprenticeships, but you can get uni degrees through them, while obtaining valuable experience, and earning a salary, and if you're looking to get away from home and/or get qualifications this seems like a pretty sound idea, as you can start saving to move out while learning. You can start them from any level, really. Have you looked into any, or just dismissed them up front?
Edit:: Another thing I forgot to mention: have you considered doing some of the free courses through
Open University just to get a taste of some topics that might interest you? You can do them in your own time, and while they don't lead to qualifications, at least you can say you've done them, which will help you find what you're into and also be something you can mention in a personal statement. At least then you can say you've snooped around!