I think at that point she was hitting bottom, knowing she was in heaven and her friends pulled her out of it and not being able to say. She saw everything falling around her and didn't see the point in it all, her songs throughout the episode shed light on what shes actually thinking and how she is torn between fighting and nothingness. To be her dancing was in essence her giving up and succumbing to the burn, so to speak until spike gave her a reason to live and a little meaning in her life