Baby drinking lesser at week 7

Hi all, I noticed that my 7 week old baby is drinking lesser (I’m bottle feeding). Prior to this, I’ve been feeding every 2 - 3 hours and 80ml per feed (total about 600 - 700ml per 24hours). Recently she has been drinking very inconsistent amount that can vary between 20 - 80ml each feed (total about 500 - 600ml per 24hours). I also noticed that she starts to get really fussy during feeds and refuses feed in the middle when she has only drank about 40 - 50ml. Is this normal or what should I do to encourage her to drink? PS: Doctor recommended 8 feeds per 24 hour between 100 - 120ml which is 800 - 960ml which means my baby is drinking a lot lesser.