breastfeeding

my one month old baby boy seems to have insatiable appetite. i had just nursed him for 30 mins and he still wants more 10 mins after. my milk seems to be enough for the first few weeks, but as he hits the 1 month mark, he kept tugging at my nipple as if there's not enough. i squeezed and there's still milk so i don't know what's the problem. he's 5 kg as of now, and wetting his diapers and pooping frequently. is this normal? anyone facing the same situation?