I need some advice

We’re about 6 months into sixth forms, and I honestly feel miserable, I’m mentally not doing well at all, I don’t feel like I fit in, even though I have a lot of my old friends, I dread going in the morning, I’m constantly anxious and uncomfortable.
I do maths edexcel, eng lit aqa and econ edexcel.
I just regret not staying at my old secondary school, the subjects I would’ve chosen and the teachers I would have had, I’ve known them since Yr7. I feel so isolated at this new sixth form, I can’t connect with my teachers at all.
My old secondary does maths edexcel, eng lit aqa and they don’t do econ.
What should I do? Even just advice mentally, the work load isn’t honestly an issue, it’s just I’m so mentally and physically drained from this environment.