I second Amamba's comment about using your real name.
For truck drivers, a lot of prescription and OTC meds will get a driver fired if found during random testing, even if prescribed. I suspect conductors might have the same problem. This is a good reason to consult your contract, union, and/or medical department in addition to the right kind of medical doctor.
Aside from what everyone else has said, you might look for a mentor in the industry. If you are not ordinarily this stressed then maybe you just need to tough it out for a while. The shortage of qualified rail workers has been in the news, so of course you won't see any time off that isn't required. And as a new hire you are probably getting the worst jobs. Both of those situations are temporary if you can hang in there long enough. In the meantime, do your best to eat and sleep right, exercise ... you know the routine.
Jobs are hard to get, you don't want to throw away this one unless you are sure it is not a good fit for you in the long term. Even then, you might want to identify a better fit before quitting and going back to school to pursue another direction.