First of all, you need to ask yourself if what people are saying about you is true. If it can appear to be true to a number of people, then they will have legitimacy in firing you and you won't be able to do anything about it. So, if anything they say is even remotely true, or can be PERCEIVED as true, make sure you seriously clean up your act or you will have nothing in court.
Trust me on this, document everything with dates and times, list every detail you can remember. Also, start documenting any 'mistakes' or 'screw ups' that anyone else has made. This can back you up if you get fired. People need to be treated equally in a job and if you get fired for something that someone else didn't, then you have grounds for a lawsuit. If you do get fired you may have a harrassment and inequality suit on your hands if you are able to back it up with documented evidence. Trust me, they're documenting everything on YOU.
Furthermore, you need to ask yourself if this is the kind of institution you want to stay at. I know I wouldn't want to work there. My advice to you is to get your resume together and start searching for another job. Life is too short to be miserable for 12 hours a day (nurse's hours, right?). Yeah, that's half your life right there.
Good luck.