TB in stomach is a serious condition​. It should not all be taken casually. I hope you are taking anti-tubercular medicines for it. Depending on hiw long you have started taking the medicine slowly slowly you will start gaining back your appetite within a month. Pain in abdomen will also reduce by the time. For now eat light foods and lots of fluids. Nausea and vometing are side effects of tubercular medicine. Along with that i will suggest take Pantop-D 1 tab daily empty stomach. This will help you reduce vometing and fulness of stomachs.