Blood in stool past 2 weeks, no pain, does seem to have anal fissure that is healing but still some blood streaks should i be about cancer?

Cancer not common: Blood per rectum is abnormal. Seems that you have explained it with the fissure. If you continue to be constipated, you shouldn't ever have to force out a bm, the fissure won't heal. Still advise you see GI doc for full colonoscopy. As often as 1 out of 3 times the full endoscopy wll find an additional problem. Usually polyps, but rarely (at your age) a cancer.