You have lost a lot of weight and that is not normal without any ailments.
Please consult gastro enterologist and get a check up with all the tests required to reach a proper diagnosis that will explain your symptoms and loss of weight. Besides endoscopy
examination of stomach /duodenum
/intestine you need tests to rule out any endocrine disorder like diabetes/thyroid disorder
etc .A thorough medical check up in a multi disciplinary hospital of repute will help you.
hope you get well soon .