Occasional bright red blood on toilet paper, wildly inconsistent bowel movement (including thin stools), no abdominal pain, very high stress, lack of exercise, excessive gas, fam history of ibs and prostate cancer. is it colon cancer?

Not likely: Colon cancer is unlikely at your age, however the bleeding still needs to be evaluated,. It may be as simple as hemorrhoids, but even that can cause anemia. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise and gradually increase the intensity as tolerated. Wish you good health.