Speaking as a newly minted RN who also has bipolar disorder (though in a less acute stage than yours), from one quirky lady to another..
..This is not the time to go into an epically high-stress major, like nursing.
I say "this is not the time", because there may be a time. It's not when you're in such a crisis state that you can't manage the early stages and nod off in class.
I so deeply understand the desire to make your mother proud, to prove that your worth her financial sacrifice. But ask yourself this: would she be happier having a daughter who is present, functional, and recognizes her own need to survive? Or does she put however much she spent on those two classes over her daughter's mental health?
(Don't answer that, I think it's obvious that I meant the former)
You're in a critical stage of a need for self-preservation. You have a long life ahead of you, and this is the time that you need to focus on managing your mental health to ensure that you'll be ready. Give yourself a semester. Two, if you need. But know that you can't push through and fix this biochemistry. And that your mother and boyfriend would rather you functional and healthy.