Hi Roxy, loss of appetite, upper abdominal pain
could be due to any one of the followig.
5.Pre menstural period
You have to do proper investigations like complete Haemogram, stool examination for anaemia. amoebiasis & worm infestation. If found to be positive then should be treated accordingly.Progesterone
results in nausea, loss of appetite during premenstural period. Your symptoms point more towards acute gastritis. Pain gets aggravated on eating. Take Rabeprazole
20mg two times a day before food for 6 weeks along with Tab. Ranitidine
150mg/day for the first two days. Avoid spicy food. Antacids can be taken when pain is severe.