Eating too much?

My baby is 6 weeks - 7 on Sunday. And eats 6-9 oz every feeding. He is also breastfed. So when I pump he seems to only be satisfied if he's getting that much? And I don't think it's a growth spurt because it's been like this for a couple of weeks. Anyone else? When he nurses he nurses both sides until empty and eats 30 minutes each side and still doesn't seem satisfied??