2 week old - any help?

my newborn usually feeds every 2-3 hours but he’s really sleepy and when I do wake him he latches on, drinks and then stops 4-5 mins later. I try latching him on again after burping him, changing his nappy etc but he still only latches for a few mins and falls asleep. And literally purses his lips shuts when I try to latch him on again....

He’s done this for the past 4 feeds he’s had. Worried he’s not getting enough milk? I even allowed him to sleep 3 hours. He wakes up himself fussing. Drinks and seems satisfied once he’s asleep but usually our sessions last 30-45mins.. and these don’t even last 10 mins.....