am I overfeeding?

Alice
Hi all, my little boy is three weeks old tomorrow and we have decided to bottle feed as breast feeding was proving impossible, he was never full or settled. At first he was having 3 - 4oz every three hours but over the past few days he is constantly hungry and can easily polish off 5oz every two or three hours. I can't seem to get him to settle until he has more milk and even then it's not for long. He was 9lb when he was born and he was weighed three days ago and was 9lb 8oz. Is it normal for him to have so much milk? I'm scared I'm over feeding him x