I think it's important too not to underestimate the depth of trauma that comes with being removed from her home and caregivers. No matter what sort of situation she was in, it is all she knows on this planet. I think that even under the best circumstances, (a child who is bonded, and has self-soothing skills), that separation would be a primal wound. But add to that a child who has additional underlying issues (neglect?abuse? Chaos?) and it's easy to see that she may just really not be capable of coping yet. All you can do is be kind, consistent, and gentle. It's heartbreaking, really, and I'm glad you're there for her.