Slander

[DroogieRN]

I've read all the threads I could find about bullying and slander, but I still need advice. Without going into too much detail, a coworker of mine hates me. She is a known loose cannon but (and even my mgr told me this) but we are so short-staffed that nothing is ever done. Several months ago, this nurse was removed from a position of Charge d/t "unprofessional behavior" (and I was never told more, nor did I ask), and I was asked to temporarily step in, which I did. Now, this coworker talks about me loudly and, from many reports, incessantly. I could ignore it to a degree but she has gone too far. Initially, I went to my mgr about it and was basically given a shrug of the shoulders, as in, "well, there's nothing I can do.". Now though, I have heard from two different people that this nurse is saying I used to be a drug user!!! (I was never a drug user). I am at a loss. Do I confront this nurse? Do I go to my mgr again? Do I go to HR? I want to quit, I am so upset. I'm afraid this could ruin my career.