My first thought after what you described is to make sure Nipo knows she is in a safe environment first. As someone already mentioned, what about secluding her to one safe small area or room? What about adding something calming like Bach's Rescue Remedies or a Feliway diffuser? Modifing the behaviour will be one step in helping your cat to get back to a regular routine.
Remember also, that cats are very sensitive creatures. So if you are frustrated to tears your cat will pick up on these vibes from you as well.

It seems you are doing everything in your power to make the changes that are needed, please keep us updated on what your vet suggests. Sending calming vibes to the both of you.