I Had A Catscan And Now Going For A Colonoscopy...I

I had a catscan and now going for a colonoscopy...I went to ER with terrible pains in my lower stomach starting on the left and shooting to the right...I then had runs with bright red blood...after having the dates can the ER dr said it was colitis...put me on two different antibiotics...feel much better...now going for the colon procedure...what r ur thoughts