5oz at 6 weeks old

Hi mamas! How much formula is your LO’s eating at 6 weeks old? My grandma keeps telling me that she thinks 5oz is to much for him. But anytime I give him less he won’t fall back asleep and he gets so mad. When he drinks 5oz he will sleep for a good 3-4 hours. But when he’s been drinking 4oz he’ll wake up within a hour and a half acting like he’s hungry again and my grandma just keeps saying “well sweetie you can’t still be hungry” since it’s only been a hour and half. I’m a first time mom and don’t want to over feed him to were he has a stomach ache.