Hi Imaginethat
Regardless, if what you think you are hearing is real or not it is still just as painful to endure. Nobody should feel bullied like that...
I have a question it's OK if you don't feel comfortable answering, but I think it may help to better gauge your present situation.

You say that this is not the first time you have experienced this issue at work. Did any of the past experiences happen leading up to and or during a psychotic break?
It's OK if you don't want to answer..I just am asking because you feel at that you are unsure if your coworkers are actually bad mouthing you or if you are just perceiving to hear mean things...
If you have had a previous psychotic break then if atm you are wavering on whether or not this bad mouthing is actually happening...then this maybe an early warning sign of the beginning of another break.. if you are able to detect early symptoms, inform your T or Pdoc asap and they may be able to tweak your meds and or do extra sessions and other coping tools, that could possibly prevent your paranoia from spiraling further down and avoid a full break. I hope that you find this post helpful...and that you are able to get some relief from the awful mean terrible things that you are hearing and the pain it is causing you
Be Well! and Keep Writing! ♡~S