newborn babies drink relatively a very small amount of milk. I was very concerned when my newborn did not drink alot like what i expected and did some research.
Their stomach capacity is very tiny so they have to drink more each time but however, some babies can sleep really well. They can sleep at longer time without milk. I was very worried at first when my boy slept more than 4 hours wo milk but my confinement lady told me not to worry as sleep is good. I just let my boy sleep through and he will not fuss much if sufficient sleep is given.
It is more worried when ur baby has a cold at such young age and maybe thats y sleep is more comforting for her at the moment. It is true that there is no medication at the moment. I dont agree with your PD that it is normal to have phlegm for babies coz at birth, the nurses shld have sucked out the excess phlegm or liquid so they will not chock.
Hanlin Li