I have a 20 month old son who came into the world wide awake--and did not sleep for more than a few hours at a time until he was a year old. He nursed constantly. Now my 7 week old dd sleeps constantly. At first it didn't worry me because she was so young, but she does not seem to be growing out of it. She sleeps day and night. I wake her for most of her feedings and she nods back to sleep before she finishes one breast. She never stays awake to nurse on both sides. She has one awake period usually from about 8:30 pm to about 11:30 pm, but other than that she sleeps. Should I be worried??