Im sorry this is so hard right now for your family. You might think of monitoring your daughters sadness just to yourself. If it seems to be persistant, you may think of getting her into therapy. The ages between 8-11 are very critical in a person's self-esteem and persistant feelings of lonliness and depression can affect that child allot if not intervened. I'm glad your daughter has a mother as sensative as you. She is blessed!