My girls have done that. the only time they did it was when my brother watched them and they were so skittish that they didnt eat much for 2 days. When we got home they wolfed down 2 bowles of food and didnt go to the bathroom until the next morning. time frame was 3 in the afternoon til 730 the next morning.
Situation may be a little different but if anything has changed a little it could be affecting her.
Is it really hot there today? Sometimes the heat will do that where they just lounge around all day. Maddie does that pretty much every day here! 8O She usually doesn't go out between the hours of 9-6 because it is just too hot. Let us know how she is when you get home. :wink: