Your problem is more common than you may think. Young people often aren’t content to carry on farming that has been a family tradition for generations. It’s hard for the older generation to let go. It’s hard for the younger person to disappoint the family, especially if leaving will mean the loss of the farm.
Your unfortunate “solution” to the dilemma may be to be isolated and depressed. You stay — but you let yourself and everyone else know that you don’t like it. I suspect the physical symptoms are related. (Just in case there is something medically wrong, do follow up with your doctor though.)
The answer is often a gradual change instead of a drastic one. You have lots of unexplored interests. A place to begin is to choose one and take a class or arrange a part-time internship. Interview people who do different jobs. Read. See if there is a way for you to take an evening off to go to class or to volunteer at a job you think you would like to pursue. You will learn more about options. A bonus is that getting out and doing something new will also increase your socializing.
While you explore, your family has the time to do their own exploring. Are there other people who can take on some of the farming tasks if you reduce your time there? Are there options for maintaining the farm they haven’t yet considered? Or is it possibly time to confront a painful reality that the farm needs to be sold?
No one can motivate you. You have to find that within yourself. No one can change the course of your life except you. You are already doing the hard work of farming and feel stuck. You have what it takes to do the hard work of taking some action to learn about alternatives to get unstuck.
I wish you well.