Also - she might still have some kind of food panic stress after fighting for her food with your mom's cats.

A vet checkup is a great idea...she may benefit from some Feliway calming spray. (The patent has come off it, so it is MUCH cheaper than it used to be!) One of my cats has to use it - He wears a stretchy collar, and I shake the bottle and put a tiny squirt right into the collar. Not supposed to go on fur or skin.)

Please update and let us know how she is doing!