Have bad gastritis ... wat do i do ? i think it is due to the poor timings of my meals.

Avoid triggers: At your age, i wouldn't expect that you have 20 stressors that are contributing to ulcers. However, you could be throwing gasoline on your fire by eating spicy foods, taking alcohol, caffeine, nicotine, peppermint, chocolate, citrus, tomato, artificial sweeteners, and other acid-triggers that are causing increased acid in your stomach. Start by avoiding these & taking antacids, zantac, (ranitidine) or prilosec.