It sounds like she has gastroenteritis with dehydration. This is generally caused by viruses which can last for about 1-3 days and are self-limiting. Bacterial gastroenteritis is usually caused by contaminated food, but generally a group of people who share the contaminated food will be sick. I would recommend: -waiting for stool studies -increasing fluids with liquids such as gatorade -frequent hand washing -probiotics -zinc and calcium supplementations can decrease diarrhea. -banana, rice, applesauce, toast can decrease diarrhea and help settle abdominal cramps. -avoid coffee, alcohol, dairy products, fruits, vegetables, red meats, and seasoned foods because these may exacerbate symptoms. If blood pressure continues to decrease and/or heart rate continues to increase, I would consider taking her to the emergency room. Also if she develops a temperature above 100.5, I would take her to the emergency room. People that are unable to maintain fluids or hold fluids down can become severely dehydrated which can result in kidney damage, altered mental status, and dissemination of infection throughout body. She will need IV fluids at that time.