My son will cry in the middle of a feeding this is the first time he's ever done it... I checked to…

My son will cry in the middle of a feeding this is the first time he's ever done it... I checked to temp , bottle was washed and dryed. It is a new type of bottle but he's used it before . He never cries every and this time it was a real cry , I'm usually good at knowing what he needs this time my mind went blank any thoughts of what it could be ?