Breast milk equivalent to water or what?

Nicole

My 4w old weighs around 11.5lbs ( haven’t had him weighed lately). He’s been taking about 3-5oz every couple hrs. Sometimes 6oz when it’s breast milk. At 6:30pm he took 8 oz of breast milk in a 30m period. Then he STILL acted hungry, rooting around and such. So now he’s working on 10 oz!!!! Is there something wrong with my breast milk? It’s like there’s not much substance to it or something. I don’t get it!