how many oz of milk does your 5wk old have?

my 5wk old was having 2oz at first, then he went up 5oz at around 4wks, hes now over 5wks old and hes only taking 2-3oz every 3hours, and hes going 6-7hours during the night... we all have a cold atm. could that effect how much he takes? hes not a small baby, was 7lb 11 at birth, and was 10lbs 5 a week ago. how much does your 5wk old take?