My 3 yo is suffering from a stomach ache and she threw up last nite. She feels sick and is warm. She had slightly irregular bowels.

Virus? The most common cause for the symptoms you are describing is a virus. The most important during this time is too make sure she is not getting dehydrated. If she is able to drink and make a normal number of wet diapers (or go to the bathroom to urinate if she is potty trained), this is a good sign. She may not want to eat much, but in the short term that is ok. If gets worse, go see doc.