There is stool meaning baby is feeding but no harm giving some formula because I did that to minimize jaundice.
My milk supply is low for my first two gals. This is my third pregnancy, I bought medela freestyle and its has the stimulation function, it's really increase my milk supply to the extend I have to pump like every two to three hours interval with about 160-200 ml from both breast each pump.
I did already let baby latch on but like 5 min each breast twice a days to stimulate the supply also... Sad to say, it's too time consuming for me as I have three kids. I decided to stop. How I wish I have this supply during my #1