I remember in the first few weeks feeling as though I never did anything else but nurse and sleep. Your dd needs practical help, the housework, cooking, etc, and reassurance that this is a natural stage and that things will settle down soon. Her and the baby will be having checkups, and the baby will be weighed. I remember the wonder at the first weighing in of my first when she had gained weight, I was doing something right!
Don't pass your worries onto your daughter, do what you can to help - i.e - laundry (babies seem to create at least one load a day), cooking, cleaning, Take the baby once he has fed, and you do the burping and get him settled so she can go straight back to sleep. These days wont last forever.