What can I do for my stomach ulcer without going to a doctor?

Worry about stomach. If you really have an ulcer in your stomach (found by x-ray or endoscopy) please don't self-medicate without a doctor's advice. Ulcers can bleed (sometimes massively), perforate the stomach, obstruct stomach emptying. Sometimes, an ulcer can form in a cancer so to avoid this possibility it is important to make sure the ulcer actually heals. Relief of ulcer symptoms doesn't always mean healing.