thanks for posting your query
From your description it is possible that your baby is suffering from gastroenteritis
(bacterial or fungal or viral or parasitic or protozoal infection
of the intestines) but also possible that given his age, he could be presenting from a physiologic GI disorder ( which is not a cause for alarm).
Since gastroenteritis is suspected, you will need to visit a pediatrician
. A stool exams (+ culture) and blood work could be done to determine the cause (if infectious) and begin a course of antibiotics that will eradicate the causative organism.
Hope this helps