I've been diagnosed of ibs 8 months ago.my question is if this was colon cancer things would be much worse by now right?"

Not necessarily: Some colon cancers are very slow growing and may not have significant worsening of symptoms over 8 months. However, the symptoms of colon cancer are usually quite different than ibs symptoms. But having ibs does not mean you might not also have colon cancer. The best way to be sure you don't have that is to get a colonoscopy. In the us screening colonoscopies are advised for all people at age 50.