Hey there,
I feel you. I used to view my parents in a similar way until they trusted me more. The thing is, when parents do this, oftentimes, they are only doing this because they want the best for you. They probably feel that good grades and a degree in medicine will bring you a stable and well-off future. You should really just sit down and have a talk with them. Explain how all their pressure is not helping and that you do not think that being a doctor will make you happy.
PM me if you would like to talk!
Kyra