Abd pain under navel. very tender to touch. watery diarrhea. cramps could it be appendix?

Possibly: The symptoms are not classic for acute appendicitis because of diarrhea and the location of the abdominal tenderness which is usually in the right lower abdomen. An intestinal viral infection is more likely.However, if pain and tenderness persist or worsen you should get examined by a physician, preferably in the hospital emergency room, as appendicitis cannot be ruled out.