Baby barely breastfeeds

La

Idk if it's just my baby but I feel like mine barely drinks milk! I always wake up engorged because he won't really drink as much when he wakes up in the night and during the day he drinks maybe 1 or 2 minutes and then gets distracted! I am so frustrated because I don't want to decrease my milk supply. I am also breastfeeding my 19 month old as well. I just feel like this baby isn't that into milk! He'll be five months in a week. Anyone else's baby like this?