I few thoughts.
1. I did give her some Nutribac last week. Maybe that helped?
2. She has a big fat tail and I would not want her gaining any more weight. I've heard they are somewhat aware of that, and can fast when they don't need food.
3. Maybe something did bother her, but she didn't eat for long enough that her stomach shrunk? Now that she's eating, she's also getting hungry again?