Hello. Amount of milk that baby is getting can be estimated from his daily weight gain, urination frequency, number of hours of sleep after feeding. An adequately fed baby should typically gain around 25 to 30 gm per day, he should pass urine around 8 to 10 times per day. He should sleep comfortably for around 2 to 3 hours after sleep. For increasing breast milk output a mother should b taking proper diet, she should be taking meals 3 times a day, should drink around 2 liters water per day and should take milk adequately. There are medicines also available to increase milk output in mother. Which you can take after consulting physician.