Hi and welcome to the forum! I am glad that I can help you.
You want to know the cause of your current condition and whether you can fly safely home and see doctor after 36 hours.
Appendicitis is a condition where the appendix is inflamed. The clinical appearance of the appendicitis starts with pain in the abdomen that in several hours becomes located in the lower right abdomen (on pressure there is touch sensitivity at the spot that separates the right from the middle third from a drawn line between the front upper iliac spine). The pain located in the upper right abdomen under the ribs may indicate cholecystitis (stones and inflammation of the gallbladder). This condition may develop into acute pancreatitis (inflammation of the pancreas), which in this case is due to a stoppage of the bile transport through the extra hepatic bile ducts as a result of a jammed gallstone. In both cases--appendicitis and cholecystitis--there is possible complication called peritonitis which, if left unnoticed and untreated, may be fatal.
According to the data that you described, it seems likely that you may be experiencing one of the two listed conditions. You should consider seeing a doctor immediately. You may need to have a blood count to rule out appendicitis. Consult with one of the doctors there about whether you may fly safely while you experience your current condition, because there is a possible risk for you to develop peritonitis or pancreatitis.
Please keep in mind that I provide with medical information only. I am not able to diagnose medical conditions online. Please see a doctor in the country where you stay at the moment, due to 36 hours is rather a long time and risky as well.