As temperatures rise and summer activities move outdoors, so do the risks of stomach bugs that can quickly ruin your sunny plans. Whether it's a picnic in the park or a backyard barbecue, food left out in the heat, or unwashed hands can lead to sudden bouts of nausea, vomiting, or diarrhea. But is it food poisoning from something you ate or a viral infection picked up from someone else? For same-day care, visit ...