This is one of the reasons why I think that observing the
breastfeeding is far more important than stool or urine output.  A
baby getting a fair amount, but not enough milk, could be having
frequent bowel movements and fairly frequent urine output.  The scales
too could be wrong, but the baby's behaviour suggest otherwise.  A
baby who is sluggish and falls asleep at the breast early, is not
probably not drinking very long.  Babies at this age fall asleep often
because the flow of milk is slow.

Get a better latch.  Use breast compression.  Switch back and forth.
If that does not work, start a lactation aid.

Jack Newman, MD, FRCPC