Is my baby eating enough?

My 7 week old baby eats anywhere from 2-4 oz every 2-4 hours. He weighs 13lbs already. I was breast feeding and supplementing the first almost 6 weeks of his life and he was consistently eating 4 oz every 3 hours. I've had to switch to just formula now since my breastmilk randomly dried up (I was freaking heartbroken.) I was concerned enough to take him to the doctor and his doctor told us he has thrush and we're on medicine now. His doctor told me the average formula intake is 2.5oz per pound. Which would put my baby at a recommended 32.5 oz daily and he's only taking anywhere from 24 - 29 oz a day. Is this enough? Is it the thrush making him eat less? I'm a scared FTM and need some reassurance.