It would be unheard of at your age.

See a doctor for reassurance and ask him or her to refer to you to a therapist. You're developing all the symptoms of hypochondria.

You don't have the symptoms for colon cancer.

Every single thing you post is an attention seeking, mentally ill rant begging for attention. Grow up and get the psychiatric help you obviously need and post your mentally ill rants in the mental health section not the cancer section.

Tell your mother.

Do you even KNOW what the symptoms of colon cancer ARE? I'm guessing you don't, not at your age. And even if you do by chance know what some of them are, you're relying way too much on Dr. Google for information. Colon cancer is very, very, RARE in people your age. If it does happen, it's usually because the person has the hereditary form of the disease. There are two types of this, Lynch Syndrome and FAP. Both of these are caused by genetic mutations, and the ethnic group which is most likely to develop colon cancer as a result of them is people of Ashkenazi Jewish descent. If you aren't in that group, you don't have anything to worry about.

you don't have cancer

that would be extremely rare for someone your age. what are your symptoms?

Don't talk rubbish, you probably have bad diet

Colon cancer seldom occurs before a person is 50 years old, and it usually doesn't cause any symptoms until the cancer has spread to other organs (which takes 5-10 years). The odds of having symptomatic colon cancer at age 16 are about 1/10th of the odds of being stuck by lightening.