After dinner, Zach figured out the problem. Her little left foot was rubbing up against the rough, plaster of her cast and it was scraping her. We put a sock on her left foot and a leg warmer over her cast and she fell right to sleep and slept the rest of the evening. She even went to bed without much trouble and slept all night, waking only to nurse a couple of times.
I'm so grateful that we (might) have figured out what was causing her so much discomfort. Hopefully, we can keep her happy and comfortable while she continues to adjust to this new phase. As always, thanks for your prayers for our precious princess!