If you have options then if I were you I’d continue with science. If you don’t get it you can go to uni out of Manchester.
You’d know you gave it your best shot rather than giving up.
Please speak to your tutors and ask for help. They will want to help you.
If you have the topics and you think your English is letting you down, have you thought of looking for online resources in your first language? That might help you
Regarding leaving home, some are ready, some not. But again give it a go. If you really hate it then you could possibly transfer for second year.
Remember, you only fail when you stop trying