bf or ff? 5-6 hrs is a little long between feedings. be careful, that can slow down development. is he/she sleeping in between? by that time my EBF ds was eating about that at night right after he cluster fed, still does. he would eat 4-5 oz every 4 hrs in the morning, 4-5 oz every 2 hrs during the day and 6 oz a couple times right before bed. how is the diaper count? weight gain?
i'm not sure what maiahlynn meant by "formula is more filling than breastmilk" but that is simply not true. kellymom.com is a great website to go to. within breastmilk there is something called hind milk (it's the human for of the cream from cow's milk). this holds most of the nutrients and fats in breastmilk and it also makes sure that the baby is full. just because something is filling doesn't mean it's good for the baby. do some research, ask your doctor or nurse. i personally don't care which you decide to do (ff or bf) but either way, frequent feedings are the key to development this young. if he/she falls asleep, strip your LO down to a diaper. you need to get that food in