Get a 6 quarts tub (15 at the most) provide 1 or 2 tight hides (6 inches plastic flowerpot saucers), provide proper temps (80-84 on the cool side and 90-94 on the warm side), leave your BP alone for a week (NO handling) and try to offer a LIVE hopper mouse.

Right now your priority is to get your BP to eat, once your BP eats with consistency 4 to 6 meals for you, you can worry about switching to F/T

The keys are security, temps, stimulation!