Hello. We've been here for two months now, but were premature. I feed …

Hello. We've been here for two months now, but were premature. I feed her formula every three hours, which means eight feedings a day. I noticed that she doesn't wake up for feeding at night after three hours. I have to wake her up and feed her. The packaging says that by two months old you should be feeding six times a day. I'm only seeing a pediatrician in a week. Can anyone tell me what they did?