Hi Carrie -
Sorry to hear that this is happening with you. I know how much you enjoy working outside the home otherwise. Women can be so awful to one another. As others have pointed out, this is a hostile workplace situation, not sexual harrassment.
It sounds like you haven't actually heard this person say the negative things herself, but have heard it from others. Are you sure it's really her? In these "she said, she said" situations, we would have HR interview the various parties and get to the bottom of it.
The only other thing that I'd say is to try to develop a thicker skin....you'll need to as a supervisor
....what goes around WILL come around.
Best wishes,
cj/