1) Put her in something smaller, a 6-15qt tub or a 10 gallon tank
2) Clutter it up with fake plants, water bowl, and two small tight hides. Black out three sides if you go with the 10 gallon.
3) Bump those ambient temps up. 77 is still a bit too cool IMO
4) Leave her alone with no handling unless to spot clean and have her be in a low traffic area
5) After about a week of having her settle into her new setup, offer every 7 days with a LIVE feeder. If you get a live mouse fuzzy/rat fuzzy you can even leave it in with her overnight since it can't harm her
Those are my suggestions as to what I would do.