Ounces of milk

How many ounces does your little one take a day? My handsome man is 3 months. I just went back to work yesterday. I fed him at 6:30am then a little at 730 then he ate 21 ounces at the sitters, fed him at 730 then he comfort nursed at 830 and fell asleep until 630 this morning. I am trying my hardest to keep up with him by pumping at work but I only was able to pump 14.5 ounces yesterday. Does it sound like he's hitting a growth spurt or is this average for a 3 month old.