I Am A BRCA 1/Triple Negative Breast And Ovarian Cancer

I am a BRCA 1/Triple Negative breast and ovarian cancer (simultaneously) survivor. Last week, I had a tooth extracted under sedation. I had been constipated prior to the procedure. By the next day, I was impacted. (Perhaps the antibiotic, penicillin, contributed to this.) A day later, I was finally able to push out 2 large masses of brown fecal matter. (It was like delivering a baby, and the hemorrhoids that followed were painful.) Thereafter, I excreted a normal sized piece of feces; however, it was half brown, and half white (sort of like a chocolate/vanilla twist serving of soft-serve ice cream.) Following this "work of art," my bowel movements that afternoon and evening came out slightly smaller and were noticeably an off-white color. I had pain in my lower left quadrant. (I usually have a high tolerance for pain...I have walked around with broken bones, teeth that have needed root canal, and, as the gynecological oncologist described it, "a watermelon and a bowling ball on my ovaries." without experiencing too much pain.) My husband convinced me to go to the ER. I took a stool sample with me. When I reached to get the bag containing the specimen the ER doctor stated, "I don't want to see that." The nurse came in and took 2 vial of blood (but left one on the food tray). While waiting, I went to the lav several times, continuing to have small movements each time. About three hours later, the doctor came in the room to inform me that my wbc count was normal, and since I am a cancer patient, he did not want to do a CT scan and subject me to the radiation. He went on further to say that if I continued to have pain, I could come back to the ER in a few days. So, a week has passed now, and although the pain has decreased, I have had at least 2 bowel movements each day, and the color of my stools is yellow! I am going to put a call into my oncologists in the morning, and I do have a colonoscopy appt. for Aug. 31st, but do you have any suggestions, other than returning to the ER?
P.S. - I am aware that diabetics and BRCA 1 cancer patients are at greater risk for pancreatic cancer, plus, my Dad had a colostomy at age 40 and ended up with colon/rectal cancer at age 66, despite the fact that he supposedly had all of that removed.