I agree with Aoha, clear liquids (pedialyte is best, especially where nausea is symptom) and soda crackers. Stay away from fiber. Flat sprite or 7-up is good if diarrhea is an additional symptom. Don't try for mass, just steady intake and monitor the out take as best as you can (fluid wise). You want as much coming out the bottom end as you put into the top end.
Add a rocking chair, soothing music, and arms that never tire of holding DD2 and she will rest AND that means y'all will get some rest. Good Luck!