Breastfeeding a newborn

Anyone else here feel discouraged about actually breastfeeding baby? Nurses keep telling me that colostrum is something you sometimes don’t see but as long as baby is latching on and sucking it’s fine that they are actually getting something. And idk how often should I feed my baby because when I feed her she falls asleep and I tried rubbing her head moving my nipple around and she still remains sleep.. the nurses here want me to aim for feeding every 3-4 hours.. I just feel like she’s not getting enough since I’m not actually seeing the colostrum. She’s only two days old now