60ml per day will definitely won't be sufficient for baby's need. if he's growing then it won't be sufficient for even a single feed. if you don't want to have medicines, then try natural galactogogues like garlic,methi,fenugreek,green leafy veggies,more water,milk,fish,egg,etc., which helps to boost your supply. if you are pumping, then pump after feeding your baby. if you are doing exclusive pumping then pump for every 2-3hrs. even if you don't get milk then pump for atleast 5mins which helps in stimulation. remember- the more emptier the breasts are, faster the secretion will be. drink a glass of warm water or milk before pumping which helps for the easier pumping. also gently massage the breasts before pumping. it is also ok to wipe your breasts gently with towel drenched in warm water. sterilize the pumping parts atleast once in a day (dismantle and put the parts in boiling water for 10mins)