Falling asleep

My son latches on well and he stares and looks around while feeding but after a few minutes he starts to drift off to sleep I then burp him and continue on the other breast I say I do this about four times but eventually he falls into a deeper sleep and won't wake back up until Iay him down in his crib he the. Wakes up crying so I check his diaper, swaddle him and he begins to root like he's hungry still so my question is when he wakes rooting do I give him more breast milk or give him his binky? Do I give him breast milk every single time he begins rooting? First time mom and I'm still trying to figure out my baby he's only 3 weeks old and idek his cries yet 😕