On Friday I noticed that Sunny was a bit lethargic and her breathing was labored. Luckily, Harry was able to make an appointment with the vet the next day. Sunny has an abdominal bulge (most likely an enlarged organ) and occasionally needs to have fluid withdrawn. The vet withdrew quite a bit of fluid and gave her a lupron injection.
She was immediately better. And so were we!
Here she is looking more herself, bright and sunny.