How many ounces a day for 3w old baby

L
My son is 3w old and seems to have an insatiable appetite! My Dr said if he is hungry, feed him on demand and if he eats too much he will spit up. He literally never spits up, and has been eating 32-34 oz a day beginning this week (which i heard is a growth spurt?). He eats anywhere from 2.5-4oz at a time. I feel like this seems like a lot. I have a one month appt next week and will talk to the ped, but I was just curious what anyone elses experience was?