I think this is normal for many people in medicine. This definitely was one of the reasons why I never considered this career. I cannot imagine how it is to work in a hospital, where misery is all around you. Obviously, many people who work there don't see it that way. They see only their impact on other people. Surely health care isn't pointless. Yes, in the end we all suffer from the human condition and we all die when our bodies fail us. But that doesn't mean nurses and doctors don't do excellent work and really improve everything we have to go through in life. You shouldn't be this cynical about everything. You are actually helping people.

I suggest you try to talk with professionals about how they deal with this and what advice they have for you. This should be part of the education track. Some people definitely just toughen it out. Others switch careers. I don't know the details of the US premed track. So you are actually in a nursing programme? There are always more options. I don't know your parents but if they are reasonable why would they oppose you changing your career path? I would understand they wouldn't be happy to see you give up completely. But it isn't that black and white, right?