What are colon cleanse health risks of years of use?

I have used various of Colon cleaners for three years, and added more then the daily amount on the bottle. It has been a year since I had them but, I feel addicted since the years of use, and after….
I have stomach problems, my chest tightens, Blood in stools, etc. I even heard it causes cancer in the stomach, and etc. Is this true… If so, what other affects?
Could I have started to kill myself without even knowing?

I have been in the Hospital last summer dehydrated.