I'm 40 and recently been have loose stools every few days and also been quite tired , do i have colon cancer?

Unlikely: At your age colon cancer is unlikely. The symptoms, however, need evaluation. Common conditions include infection (food borne Salmonella , entero viruses)food allergy/intolerance, (eg Lactaid deficiency gluten sensitivity etc etc) See a Gastroenterologist and get these symptoms evaluated but don;t think the WORST FIRST.....Be well and Hope this helps! DR Z