Narcissistic abuse is often carried out in the absence of other witnesses. This leaves the target in a strange position. You suffer a lot, but it's unlikely anybody will believe you if you tried to describe what you're going through. A malignant personality carefully plots and plans how to bring you to your knees with all of the precious of a chess master.
She spends a long time studying you. She makes sure her nasty, demeaning remarks are said when no one else can hear them. Her actions can always be taken two ways. So if you decide to use someone else as a sounding board, they'll probably think the incidents you're describing are too trivial to worry about or, perhaps, you are blowing them out of proportion. Narcissistic abuse unfolds over time. It's the total number of mini attacks, all added together, that can destroy someone.
The fact that no one would believe you, if you told them what was going on, is maddening. For a number of reasons, this is why I'm convinced it's best not to talk about what's happening with your other friends or acquaintances, and most especially with your work colleagues. First of all, they'll undoubtedly think you're overreacting. (Narcissists like to set up scenarios designed to make you look silly.)
Second, malignant personalities like to arrange instances where other people get to take a whack or two. This is known as bullying by proxy. This is one of the reasons they work so hard to turn people against you, because they use these flying monkeys to dole out some of the abuse. (Bullying by proxy allows them to operate under the radar. Few will suspect they're capable of such wickedness when no one sees them in action.)
So the person you most suspect of causing all the trouble may not be the main bully, just a pawn. If you do talk about this, then, later, you'll have to explain that the pawn wasn't such a bad person after all, compared to the real bully, who directing the players.
Sometimes, its' better not to talk about evil. Your best support during this time will likely be found online. Learn all you can about how narcissists operate, so you can extricate the current one from your life and make sure no more morally disordered people gain entrance to your world.