Over feeding?

My formula fed 4 week old ate 34 oz yesterday. He didn't spit up any of it. I made him the usual 3 oz every 3 hrs. I tried everything to soothe him after he ate like holding him pacifier etc. He just kept rooting and chewing his fingers. I made him an extra oz each time he did that because at night when he sleeps longer he may want 4 oz to hold him over until 5 hrs later. But he still wanted another oz! I ended up giving him 5 oz at least twice. Usually he will eat 20-23 oz. He weighs about 9 lbs now was 7 lbs 8.5 oz at birth. Growth spurt or am I over feeding? 34 oz is A LOT.