Hi. Thanks for your query. Noted the history and understood your concerns. Nausea and bloating after eating food at the age of 14 is indicative of gastritis related problems or some sort of gastroenteritis wherein there is inflammation of colon hence the feeling to pass motion but no actual stools coming out, this is called tenesmus. I would advise you the following in such a situation: First of all talk to your parents or guardian. Get an appointment of a qualified Doctor since you are in china. Get the stool tested. Clinical examination, evaluation and correlation with stool report will give the most proper diagnosis so that you will be prescribed most proper medications. Also watch for the source of water, food which may need change or purification. Also watch for the foods and beverages that instigate or enhance your problems and stop these altogether.