@led No, there isn't something "wrong" with you. I think we should first consider that most of the people on Connect are American, and some are Canadian. I'm not sure where you are but I can tell you that the vast majority of Americans are not as concerned about pleasing their parents and duty, as you seem to express. Neither is wrong or right, but different. Advice here is being conveyed from another cultural lens/perspective (American).
When you express feelings of hopelessness and worthlessness, Americans take this as a sign that you need mental health services. Mental health issues are much more socially acceptable here than most places. I would say a good portion of the population goes to counseling or seeks a medical professional for mental health medications at some point in their life.
From my American cultural perspective, it sounds like you are not passionate about school and/or medical school may not be the right place for you. It's either too difficult or it just isn't right. I don't exactly know what that must be like for you but I'm sorry you are feeling hopeless. Everyone has specific talents and passions and in my opinion, it is a parent's job to help you self-actualize into the best and most authentic person you can be. Again, this is my American perspective that stresses individuality over the group. I know this is not how most cultures operate. (I have a degree in Anthropology and Counseling).
Regardless of the culture, I think it is safe to say that even if medical school isn't right, you still have a life worth living. You are a unique person that has something to give the world and you are deserving of fulfillment.
I'm going to quote Einstein. Have you heard the quote....
Everybody is a genius . But if you judge a fish by its ability to climb a tree it will live its whole life believing that it is stupid."
I use this quote to reiterate, not everyone is the same. You are not your siblings. You are unique. You are not better or worse.
I hope that you find a path that allows you to express and realize your unique personality to its fullest potential.
As a side note, is there anyone that you can talk to at the school. Are there any therapist or guidance professionals?
Wise words and I had never seen that quote about the fish....thankyou!