Normal can be anything from every few days to several times a day. I know this because my wife is the former and I'm the latter so we were wondering who was the weird one. But we're both normal just at opposite ends. But if every few days you have diarrhea, that's different.
One common symptom of the bowel cancer is blood in the stool, but not in all cases. Blood in the stool may appear from many other reasons, though (bowel inflammation for example). When your problem started? Any other symptoms, like feeling tired, loosing weight? What do you eat? You've said you drink many bottles of water each day. Can you explain this a little? There are many causes of constipation and diarrhea: Constipation: food without fibers, innactivity, psychological, some underlying disease, medications... Diarrhea: food poisoning, inflammation... One type is "paradox diarrhea" in constipated persons. Hardened stool can stuck in the large bowel, and liquid stool passes over it from time to time. There are lot of possibilities here. If you want further discussion, you'd need to tell more about your symptoms, how long they last...
There is a type of tiredness when you feel weak without obvious reason...this can be a sign of disease.