If she has a fever I would call the parents for pick up. Otherwise I would let her be. She is trying to cope and her bed feels like a safe place for her. Check on her continously offering smiles, soft voice and reassuring words. Poor tyke is not feeling well and not up to her new situation and dealing with cold. If she is making sounds like she wants up then get her up again giving her lots of cuddles and attention. Feed her as you do everyone else and then put her down for nap at usual time. Keep checking to make sure her cold symptoms do not worsen. Good luck