Do the symptoms of stomach ulcer tell you whether or not you have a big or little ulcer?

Size doesn't matter. Regardless of size, if you really have an ulcer in your stomach (found by x-ray or endoscopy) please seek doctor's advice. Even small ulcers can bleed (sometimes massively), perforate 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.