to much for his age?

Sadie
So my baby boy is 2 weeks old. He weighed 8lbs 7ounces when born and I was not producing enough milk so I switch to formula for him. He was taking 2oz every 2-3 hours the first week. He now weighs 9lbs 8ounces and starting last night he's been hungry after the 2oz and he's been drinking as much as 4oz every 2-3 hours! Is this normal for a 2 week old to eat 4oz?