Ay nako, normal yan sa newborns, they do fall asleep fast after feeding kasi pagod sila! The best signs na nabubusog siya ay kung may wet diapers siya (around 6+ per day by week 1-2), poops are yellowish, at hindi siya constantly crying from hunger throughout the day. May friend din ako na first time mom and kinabahan niya rin, pero OB namin said kung laging alert at active ang baby between feeds, okay na, kaya I'd suggest checking in with your pediatrician or OB lang para ma-guide ka properly on what to look for, every baby's feeding pattern is a bit different! In the meantime, check din kung okay ang latch para sure na efficient ang feeding, and don't hesitate to reach out to a lactation consultant kung may clinic nearby, sobrang helpful talaga nila.