I keepnyawning all day long what could be wrong?

ANXIETY can cause: you to yawn frequently,or you could be tired.

Must be tired. : Besides not having proper sleep sometimes boredom or stress also bring on yawning. Make airw you rest well and next day exercise This too shall oas

Fatigue: Yawning is a sign of exhaustion and tiredness. Typically when your body is tired yawning helps to take a gush of fresh air forcibly. It is a reflex that if you someone else yawn, it is contagious and you will also yawn.Otherwise it is fine

Tired?: The obvious answer is you are not getting enough rest. There are conditions that could cause yawing but they are far and few in-between like vagal stimulus or narcotic withdrawal.