Constipation, Hurting Abdomen And Gallbladder, Indigestion, Diverticulosis, Taken Cipro And Flagyl, Done CT Scan, DRE, Blood Test, Colonoscopy, Had IBS. Possibility Of Colon Cancer?

Question: Hi i am a 52 year old male 6'0 213lbs pack a day smoker. been constipated lately. one day wiped after bowel movement had small spot of blood on TP. Went to CVS bought FOBT did this for 2 weeks, all negative. (except the time i saw it on toilet paper which turned the FOBT paper pos. but only a small spot turned) Then again strained some and wiped, blood about 1/2'' long and 1/16" wide on toilet paper. Abdomen area always hurting maybe a 3 on a 1-10 scale, sometimes though it hurts in area of gallbladder. Nausea almost daily but not real bad.Along with indigestion. Went to ER one year ago with same symptoms except no blood in feces. They did CT scan said showed diversticulitis, gave cocktail of cipro and flagyl for 10 days, all was fine, this time went to ER because of blood on toilet paper. He did a DRE and blood work. Said he felt nothing and saw no hemmroids. Blood work came back fine and said since it had only been a year since the CT scan did not think it was cancer since nothing showed then. Said it was the divers again gave another 10 day of cipro and flagyl, and scheduled me for my first ever colonoscopy. Plus told me to take a fiber supplement. He also did an FOBT and found it to be negative. Finished the meds today, but still have the pain, bowel movements are easier but seem to be a little flatter than normal, not ribbon per say but more like if you took a polish dog and shaved off about 1/8" off one side. My consultation with GI is tomorrow. A little worried does this sound like colon cancer and progressing? Have had IBS for 20 years, but not bothered me in sometime. (rotating constipation and diarrhea) Feel good otherwise