If a baby is getting enough breast milk, he/ she would be able to sleep for around 2 to 3 hrs after that. The baby would be passing urine around 5 to 6 times in 24 hrs and going weight @ 30g per day.
Next Steps
Breast feed from one side for minimum of 20 minutes. After that, try to express milk from same breast and offer it to the baby.
Health Tips
No need to measure the amount of breast milk by manually expressing and trying to evaluate the adequacy of milk production. Remember, many babies can cry due to colic pain and not due to hunger.