as long as you don't have bright red blood in your poo than it sounds like bad gastro to me, if you can't stop vomiting or get unbearable abdominal cramps and a high fever go to the ER, you can get meds to help with that and some investigations, keep hydrated, as long as you are still weeing than you will prob just have to ride it out hydration and things like gall stones, appendicitis etc are the main concerns but you said others have had it lately too. You poor thing must be awful.