Well, you know what you need to do.

1. Get the mania in check -- probably means seeing a pdoc
2. Take tomorrow in stride and DON'T assume people are talking about you or know you're BP. You know she gossips, but you can't be sure she has said anything to anyone else without evidence.
3. Talk to your boss if you have to if that can help contain this perceived "threat"

Honestly, worse things can happen besides people knowing you're BP. At least you have your health and haven't done anything dangerous. ((HUGS)) You're still capable of caring about the consequences of your actions. This means you can safely see a doctor about a med increase for a short amount of time before requesting for the doctor to reduce the dose again once you're feeling stable.

BipolarNurse, you're a smart cookie. I know you'll survive this little slip and become a stronger person from it.