Newborn and pacifiers

My daughter is 3 days old. Breastfeed and bottle fed with only breastmilk. She was killing me with constantly being on the breast as comfort like I was her pacifier. I was getting no sleep so I decided to give her a pacifier for comfort aswell. She still latches on my breast maybe not the best but she's still able to eat and unlatch when she's done. Ive noticed that when she unlatches she snaps out so I usually try to put her on so I'm assuming she's either hungry or for comfort. How do I tell when she is hungry verses when she wants comfort...? I'm assuming she's hungry when she refuses the pacifier completely but I notice sometimes she doesn't want either and just wants to scream and cry (unlatching from breast and spitting out pacifier)