What Does Timely Vomiting And High Fever In Toddler Indicate?

hello my 20 month old never gets sick toddler vomited last night while drinkinghis milk and was accompanied by a fever. We gave him tylonal and then advil the four switch every four hours his Dr. had said. This mornit still didnt quit have his appetite back. I kept a close eye onhim assuming it was a 24 hour bug,I am a mother of three boys so I try not to jump the gun. Tonight same time he had a bm which was very loose plus vomited,and thenthe fever came on,,, around !00.1. He has had a loose bm again. Prior to this eveing he had some very sour acid like smelling gas. Def calling Dr. andseeing him first thing in a.m.Any ideas on what this could be, noone else in fam has been sick(yet). Thank You...ShayShannon&Shanes SuperMommy