formula feeding every two hours?

Alice
My baby is three weeks old and was weighed a week ago at 9lb 8. He's taking 4-5oz of formula every 2-3 hours. I've given up without breast  feeding as I couldn't fill him! He's having between 28 and 34oz each day. Is this too much? It says only to be giving him 25oz max on his milk so I'm worried he's having too much.