how can i get myself motivated in school?

I would have a serious conversation with yourself if medicine is what you actually want.  I'm the last guy to deny someone their dream, but without the strong desire to  motivate yourself to do all the things needed to accomplish it, than it may not be for you afterall.

Do school with a friend on face time who can explain things if you need help and make sure you are in a quiet place. Or once corona is over you can get a tutor, because I had a D in math this year and I got a tutor and now I have an A.