22 year old male terrified of colon cancer my appetite hasnt really been there lately how likely is it due to colon cancer what are my realistic odds?

Odds are small.... Colon cancer would be quite rare at your age. Are you having symptoms such as bleeding from the rectum (not usually cancer - more likely to be a tear or hemorrhoid) or black bowel movements? Do you have a family history with many folks who have colon cancer at young ages? Have you been advised by a doctor to start having colonoscopies early? If not, you may want to talk to your doctor re: anxiety.
Very unlikely. Great majority of cases after age 50. Earlier cases usually have a strong family history of colon cancer, or familial polyp syndrome_ fairly rare. Bad appetite can be due to lots of causes in a 22 year old. Colon cancer is a very unlikely cause.