hi! my baby girl is three months old. we usually wake her up every 4 hours for feeding. as recommended by the doctor due to some feeding complications, we feed her formula milk at night. there are times when if not woken up, she can sleep for upto 7hrs at a stretch. now on a contradiction, we've been told that we must not wake up a sleeping baby. what should we do? should we wake her up every 4 hours or let her sleep?