Sixth form is not working for me.

I am really really struggling with sixth form. The whole thing is a bit of a long story but there was a small sixth form that I desperately wanted to go to, I wanted to study the IB there and I'd planned and researched the whole thing - I was absolutely sure that it was the best place for me. I applied to two other sixth forms as "just-in-case" but I was pretty sure I wasn't going to need them. Until about this time next year they announced that they hadn't got enough applicants and were closing. I decided to go to my second choice sixth form instead, which was also a small location, only to find that their college bus was no longer going past my area and without it I wouldn't be able to get to the college without a 2 hour bus journey each way (I live rurally). So I ended up going to this massive sixth form which is known as the "smart kids school" in my area.
I have no problems academically (I got 8 9s and an 8 at GCSE and I love learning) but in all other respects I'm really struggling. I'm spending 12-13 hours a week on public transport which is exhausting, as well as 15 hours in lessons and we're supposed to be doing 17 hours of independent study per week. I'm autistic and I find the sheer amount of students so overwhelming to the point where I can't hang out in the main social areas and spend basically every break and lunchtime in my school's low sensory area, which is calm but lonely. Because my school considers itself "aspirational" they love to pile on the pressure and EVERYTHING is compulsory - we have to do EPQ, we have to do at least one hour of an extracurricular activity per week etc. etc. I've had several meetings with my tutor and in the latest we asked if I could drop EPQ but I was told that I couldn't because "you just don't do that here". The whole environment is so competitive and toxic and so far I've just been pushing myself through it but it's just all getting a bit much. I feel so drained and burned out all the time to the point where I'm struggling to do the baseline level of homework and I have no energy left to do the things I enjoy so I just spend loads of time scrolling, which I know isn't good for me. I don't want to keep having to push myself through it but I also don't know what alternatives there are.