Suggest Treatment For Stomach Pain And Vomiting

this morning I woke up w a stomach ache, soon after began vomiting (very painful in mid abdominal area)Shortly thereafter I bagan having brown diahreah. Both were occurring every 45 mins-hour. Early after noon I stated taking some PEPTO BISMAL, and my doc called in a script for 8mg ONADANSETRON which I also started immediately.
Since taking the ONAD(2 doses)I am no longer vomiting, but still have mild naseau. The diahreah seemed to have subsided for a few hours, but returned about seven hours later, two separate episodes of BLACK, TARRY, EXPLOSIVE,