C.M.
Why are you trying to do everything but nurse her at night? I understand that you don't feel 100% well because you are getting interrupted sleep, so how about adjusting your life so that you take a nap during the day with one or both of your children when they nap? And, are you co-sleeping? Your body will fall right back to sleep if you don't have to wake up enough to be mobile. After a while, you may find that you hardly remember nursing during the night while laying down because you may stay in a drowsey state while nursing. The surge of prolactin has a relaxing/Valium effect on the brain. A bigger bed might be in order to accomodate this way of parenting. Maybe this is too much of a lifestyle shift in thinking about things, but that is how many nursing moms survive the early years. (See Dr. William Sears The Baby Book and La Leche League's the The Womanly Art of Breastfeeding for support.)
Your daughter's issue is not about caloric nutrients, it's about maternal comfort and neurological organization that she is recieving when she night nurses. Many times babies this age are becoming too busy/taking in their world during thier waking hours to feel the need for this sort of care, but when she's quiet and your quiet, nature tells her she needs this. The suck, breath, swallow pattern is very neurologically calming & organizing. You are enabling her to build strong neuropathways that relate to emtional attachment, which relates to attention & concentration which benefit her for the rest of her life, particularly in school. (Google Allan Shore to see for yourself.) Intuitive mothering is another phase of a woman's development, if you decide to partake of it. It will stretch and grow you like no other way.
Good for you for being attuned to your daughter's persistence in trying to get you to figure out her needs! And goooo baby for demonstrating such perseverance in trying to get your mama to figure you out!
Every child is different, so if you find youself saying, "but my older wasn't this way..." just give that up and accept each individual's differences.
Happy adjusting.