Hi, Thanks for writing in. Cancer symptoms of bowel includes sudden change in bowel habits like constipation or diarrhea. Some people also experience bleeding in stools. Unexplained loss of weight can also be seen in bowel cancer. Since you have recent onset diarrhea then you should get a detailed cancer screening examination done. I suggest you get your stools tested for occult blood till the time you have to wait to see your surgeon. If there is occult blood in stools and as you have strong family history therefore you should get a colonoscopy done. It will locate any abnormal areas of polyps which are precursors to colon cancer. Doing colonoscopy and ultrasound scan of abdomen might highlight any suspicious area causing you the strange feeling whether inside the bowel or anything on the outside. Please do not worry.