How much do/did you feed your 3 week old?

Basically the question. I have a 3 week old who is formula fed and I have no idea how much food to give him. Yes, I know it depends on each baby, but I would like to see some opinions.

I feed him with 60 ml every 2 hours or even less (when he asks, I don’t wake him up to feed him or let him starve) and then there’s a period of a few hours, generally at night, when he starts being really fussy, he won’t settle or sleep and will eat non stop. If we keep feeding him, he will eat until he can’t no more. I am a first time mom and I have no idea if this is normal, if I should keep feeding him or if me feeding him is going to cause some damage to his stomach. I have doubts because my GP said that 60 ml every 2 hours is already too much for his age and that he’s probably crying about something else, not because of hunger… but I change his diaper, I bathe him, I let him sleep as much as he wants throughout the day etc.