Toddler with a stomach bug!! Help!

So this is the first time my almost 2 year old has really been sick and I feel like a total spaz. He started throwing up Tuesday night and puked once on Wednesday afternoon. Thursday, Friday and today he's really been very sleepy. He wakes up to drink water, eat (what little I can get him to) or to nurse. Then he just wants to be carried, lay around or sleep. He hasn't ran a fever at all, which is why I haven't ran him to his doctor.. But his lack of energy is starting to worry me. Anyone else experience this with their little?