G.B.
Is there NO other symptoms?
Aside from an infection, or constipation, the other possibility is low adrenal hormones.
Cortisol or aldsoterone. They control stomach acid, glucose metabolism and more. When someone gets low on these hormones, they will vomit, they will have nausea all day- or comes and goes, they will have insomnia issues, concentration issues, headaches. As it progresses: fatigue, leg pains, pains in hips, knees, low back. (which is typically blamed on growing pains because most doctors have ZERO training in hormones in med school). Hormone issues are now at an all time high because of all the chemicals in the environment, but also alot of the prescriptions and antibiotic drugs disrupt/affect the endocrine system.
Celiacs is caused by low stomach acid issues (low hormones.)
Dont rule out constipation. Try giving more water and also, a product called CALM. It is a magnesium product that will keep the stool soft and help them go more.