I thought I had a UTI, bladder or kidney infection but....?

After 4 days of extreme discomfort in my abdomin and middle to lower back I went to the doctor. I have extreme pressure and pain in the rectum when I go to the bathroom, both urinating and bowel movements. The doctor found blood in my stool and now I am having a Ct scan in the morning. Anyone experience this? Any ideas what I might be dealing with? I am 43 years old and have had 2 C sections.