"My truth", "careers are BS", "not my dream job", "stuff I'll never use"---yup, you've honestly just confirmed that you basically are or are just like a whiny millennial. And, don't give my that crap about 'labels' either because I just don't care.
"Your truth"---no such thing. There's true and there's false. You may have opinions, but there is only one truth.
"won't change the world"--this is another unfortunate misconception like the 'dream job'. Relatively few individuals on this planet have 'changed the world' on their own. It's a collaborative effort. That's not skepticism or pessimism, its simply a quantitative reality. You'd be better off and be less disenchanted if you stick to what human beings are really here for--each other. You CAN make a difference in people's lives, and, that's what the what the world is really made up of...
"Careers are BS"---I've heard variations of the same thing over the last decade now from the same generation. "People weren't made to have careers." Not true--we just don't take as good of care of ourselves as we used to, even when we possess the knowledge to do so. That said, yup--your body is going to break down a bit every day no matter what you do. Wanna be a job bum, moving from career field to career field for the rest of your days? Well, good luck providing any financial stability for your family. Unless you already have a pension from somewhere else, you might want to look up what history, experience, and statistics say your chances are of doing very well without a 'career'.
"Not my dream job"--Some people have theirs land in their lap, some people find it after a lot of hard work, but the reality is that MOST people don't find their dream job. The hard truth is that most people have to work to find a balance between work, family, and what makes them happy. That's just life. I know the younger generation thinks they can arbitrarily change that little bit of reality, but it hasn't been panning out too well for them so far.
"Stuff I'll never use"--ah yes--spoken like one with years of experience in a given field. I've at least got a bit of experience in the medical field--I think maybe you should be an EMT or Paramedic. What you 'need to know' and the 'stuff you'll use' is a bit more defined. You don't have QUITE the autonomy (I'm going to draw the ire of a few paramedics with that statement for not expounding on my point--yes, I know that it's not completely true--autonomy may not be the right word). What I mean is, what you can and cannot do as an EMT or Paramedic is defined more by protocol and algorithm and is a much more specialized field (pre-hospital care)--nursing is all over the place. You also spend more time with patients as a nurse and have to apply a more broad approach to medicine and all-around patient care. To be fair, I'm just on my way to a 'career' (there's that dirty word) in nursing too, but, having spent time as an EMT and a military medic, I'm very rapidly learning the very important differences between pre-hospital and in-patient care. One isn't necessarily more difficult, but, they are very, very different.
I'm also in my mid-40s and came to the place I'm at having spent 15 years in one 'career' that I left before it became a dead end, 3 years in one that I loved that came to a premature end (my 'dream job', if you will--driving locomotives), and another 13 years, throughout all of that, in part-time endeavors like the military, firefighting, and EMS. In my humble experience, people with your attitude (one of arrogance and entitlement) don't last long in any career where they start off thinking they know what they 'need' to know and 'don't need' to know. That attitude on the railroad, in the military, and in the fire/EMS service will get you and/or someone else killed. I doubt the stakes vary too terribly much in the nursing field.
It seems you're trying to find as many people as possible who will validate your feelings of frustration, and, inevitably, you have and will get a few. I'm at the PEAK of stress and frustration--I work full-time, go to school full time, I have 4 kids (my oldest is 20, youngest is 12), and a wife who is MORE sick of my schooling than I am. Sleep? What's that?!? But, it's all temporary. It's crap that you just have to push through, and, if you're THIS frustrated THIS early on, and you are THAT concerned about your time, I really doubt that this is the program or 'career' for you...