I have to have a colonoscopy??? Pretty worried?

Your doctor will check for many things during the procedure. In your case, they are primarily looking for the cause of your blood loss. Ulcers, diverticula (small protruding sacs in the bowel - mainly caused by constipation), polyps (which can turn into cancer eventually), spastic colon, hemorrhoids, colitis - all are conditions that your doctor will be able to diagnose through the colonoscopy.