It could be that she is trying to figure out why the house is so quiet, and "where is everybody?" I don't know if she's depressed, just out of sorts. It will take some time for her to adjust again to everyone's routine. Just keep reassuring her that your still there for her, maybe give her some extra attention for a little while, and try to keep to her routine as much as possible. I think with time she will be back to her old self again.