Constant nursing for past 8 hours +

Baby is 4 days old wanting to nurse around the clock, no naps just wants to eat. If she does fall asleep and I lay her down she will wake up reaching/looking for breast! How is she not as exhausted as me?! She will take the pacifier for a few minutes maybe. I am starting to produce milk...Any tips would be appreciated, I also have a 2 year old so nursing this often makes things very difficult to give her some attention as well! Oooofta!