I Am A 24 Year Old British Female,68kg And 5ft

I am a 24 year old British female,68kg and 5ft 8.
I am in Cambodia and picked up a severe case of Dhiarrhea.I have been going to the toilet at least once every hour have very swollen stomache and very intense stomache pain,like cramping and wave motions,this pain causes me to gag but I am never sick only bile. This is the fourth day now can you make any reccomendations? Many thanks