What Causes Pain In The Upper Abdomen Along With Nausea And Diarrhea?

My daughter (19 yo) is currently in Laos, after a month-stay in Vietnam and Cambodia. She started a 100 mg. a day dose of Doxycycline prior to leaving the US. She has been experiencing upper abdominal pain, vomit, nausea, diarrhea and acidic burping for seven consecutive days. She tolerates small amounts of electrolytes. On day three she commenced a five-day Ciprofloxacin treatment. On day five she was taken to a clinic where she received a saline/glucose IV + anti-emetic, and some other unknown medicine (possibly for the abdominal pain, but it was not an opiate or other analgesic). After 14 hrs. she was released from the hospital and given Omeprazol and an anti-emetic. She felt better the day after being released from the hospital, but now feels worse. The diarrhea continued and the nausea and acid reflux returned, along with headache.