Thanks to everyone who answered in this thread... Here's the update - turns out she was just going into shed. You can actually see in the picture above that her belly is a bit pink - now she is turning more opaque. It's funny, I can't even remember the last time she's shed, so I'm very pleased. Also, the male who she was paired with is also in shed... maybe they planned this secretly in the night!

Anyways, Robin I plan to follow your advice, and pair every 2-3 weeks instead of continuously - when I think about it, it makes a lot more sense anyhow.