What Could Be Causing Ongoing Stomach Pain And A Reduced Ability To Eat Or Drink After 4 Months Of Symptoms?

Hi I’ve been having stomach pain for 4 months now and I’ve tried everything and nothing has worked. Recently I haven’t been eating and drinking properly. I only finish half or have a few bites of my food and then I can’t eat anymore. And I only have a few sips of fluids and then I can’t drink anymore.