My 22 month old son woke up a couple hours after bedtime last night throwing up. He threw up several times during the night, and has not kept anything down today. Like he had some water and it immediately came back up and splashed on the floor. Other than the puking, he seems happy and normal though. He's only ever thrown up once before and it was an isolated incident, so this is a first. Does this sound like a basic kind of stomach bug or should I take him to the doctor? I hate to spend the time and money for them to tell me to let him rest and give him fluids, but it's also new for us so not sure how concerned I should be.