It sounds like she's just getting used to her tank. Keep the lights low, and obviously make sure she's got some hides and places to retreat too, and if possible avoid too much loud noise. Leave the lights off if you have tank lights.
If she's gone into an uncycled tank, you'll need to monitor the ammonia, nitrite and nitrate daily until the tank is cycled. When the tank is cycled you'll have an ammonia reading of zero, nitrite zero and nitrate between 10 and 80.
If she doesn't eat the food, remove it after an hour or so, so it doesn't foul the water.
Good luck.