Every baby takes its own time for feeding. And during growth spurts, baby needs more milk for its growth. So baby may feed more frequently or longer during these phases. Sometimes babies may suckle at the breast for just comfort too. Babies less than 2 months old generally do not have night / day awareness. And are more awake during the night. Check if the room temperature and clothing is too warm or cold during the night. Check for wet nappies. Check adequacy of feeds. If baby is gaining weight as per chart, passing urine 8-9 times in a day and passing stools 3-4 times then milk is adequate for her.