hello dear, 
i understand your concern ,
ibubrufen should newer be used for 
abdominal pain since risk of 
gastritis and 
peptic ulcer.
best pain killer is 
buscopan or meftalspasm or mefepenic acid.
according to your symptoms it is 
gastroenteritis.
it may be due to eating out food outside, parties,etc
for this i used to prescribe following treatment in my clinc.
1)TAB AFLOX TZ TID FOR 5 DAYS
2)TAB SPOROLAC BD FOR 5DAYS
3)TAB PANTAPRAZOLE 40 MG OD EARLY MORNING BEFORE BREAKFAST.
4)ORS SOLUTION OR ELECTROLYTE SOLUTION WHEN EVER YOU GOR FOR LOOSE STOOLS.
5)ANY CRAMPY PAIN USE TAB BUSCOPAN BD
IF NOT RELIVED BY THIS TREATMENT,
INCREASE IN AMMOUNT OR NUMBER OF TIME STOOL OR FEELING DEHYDRATED MEET DOCTOR.
THANK YOU.