Welcome Dana! Glad to have ya.

Don't worry about the size of the prey(unless it's a pinky mouse or a medium rat). I have adult girls that are eating adult mice(4-6 at a time) and they gain weight like nobody's business. It's personal preference though and whatever the snake will eat.

I'd do what Robin(Rabernet) suggested and move the snake to a small tub enclosure with small hides or a small kitty litter pan, keep her in a dark, quiet room for a few weeks leaving her totally alone except to give water, and then try to feed a small adult mouse. Hopefully she'll settle in and begin to eat on a normal schedule.

Good luck!