Baby falling asleep during feedings

My baby is a week old and is falling asleep during her feedings. I know in the hospital they said she’ll fall asleep when she’s satisfied, so i don’t think this is a problem... however at night she then wakes up every hour or so because she’s hungry. She will feed for about 8-10 minutes before falling asleep. She can last hours between feedings during the day, though... Any tips on how to keep her awake during feedings to get her to sleep longer at night, is this typical/normal, or more like day/night reversal?