Breastfeeding trouble shoot

My 20 month old is behaving abnormally while nursing. Normally he latches on and just chills. Well here lately he will latch on and off and eventually just give up and lay on me instead. He has been on and off sick and has some health issues but none of that has ever affected his nursing ability except when he was a newborn preemie in the NICU with a weak muscle tone.

Has anyone ever had their older nursling pop on and off like they are frustrated or not able to latch well? What was the end result? He currently needs a nap but is popping on and off so much he isnt able to go to sleep 😩