My LO is 3 months old, he hasn't slept more than 3/4 hours at night until yesterday. When he woke after 6 hours I fed him just like every morning and once he was finished he burped and spit-up a bright yellow glob. It was enough to stain his shirt and the spit-up rag bright yellow. Maybe tummy acid, but I have never seen it before and his belly was full. Any advice would help as all doctors are closed today for the 4th.