I Had A Routine Colonoscopy 6 Days Ago With One

I had a routine colonoscopy 6 days ago with one polyp removed. Immediately after I had sharp pain in my right side that felt like appendicitis (already had that removed a few years ago) today I had a bowel movement that was all bright red blood each time, no stool. I've had 4 more just like it with a 16 ounce amount of bright red blood. Called Dr and they said go to ER. I went to ER and the blood tests were normal, so sent me home. I'm concerned because of the frequency and amount of blood. Any insights as to cause and solution?