Everyone has lots of interests and several hobbies. That doesn’t mean they all need to be majors. A major should be something that 1) you want to study in some depth for four years, and 2) you think may be good preparation or a foundation for a set of future careers you may be interested in.
Particularly when you think about pre-professional majors like nursing or journalism, I think you should not only think about the classes you enjoyed but whether you would like the day to day work of doing that job. Nursing can’t really be boiled down to an anatomy class: it’s a necessary subject but not necessarily akin to what you’d do every day. Have you ever volunteered in a hospital or shadowed a nurse? Many would be delighted to show you around. I love writing as a hobby, but writing on a deadline in the style that journalists do would be stressful for me, and there are lots of other elements to a journalism job to consider. So liking to write in and of itself isn’t enough to be a journalist. You can do an internship in the field in college, or join the college newspaper, to see if it resonates with you.
Also consider that there may be careers you’ve never heard of that are appealing to you. I’d never heard of the career I’m doing now when I was in high school - or college, for that matter. I found out about it maybe 3ish years ago, when I was in graduate school.
These kinds of questions are less relevant if you major in, say, sociology or physics - because those majors lead to a wider diversity of careers. However, that’s not to say that many nursing and journalism majors don’t go do something else. Nursing majors, particularly, could do a wide range of health-related careers - like pharmaceutical sales, or consulting work, or hospital administration, if they decided not go into nursing.
There are unhappy people in every career. I don’t think there are necessarily more unhappy nurses than there are as unhappy journalists. My mother’s a nurse, so I grew up around nurses, and I know many nurses who love the work they do (including my mom, who was a mother/baby nurse for years and is now an elementary school nurse.)