Is he eating too much?

My son is just over 3 weeks old and is always hungry. When he was first born he'd eat 2 ounces every 3-4 hours. Now he eats 3-4 ounces every 2 hours. It's non-stop feeding around here. He gained 2 pounds in 10 days and Doc said that's a lot. (Baby was 6.4 at birth and 8.2 barely 2 weeks later.) Told us not to go over 4 ounces for the next month. Just curious how much other newborns his age eat and how often?