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Your embarrassment is understandable, but guess, you will have to be practical. Since there is blood which you can see, it is coming from the lower gut. This can happen in hemorrhoids, rectal polyps, diverticulosis (outpouchings from the bowel wall), inflammatory bowel disease, or dysentery.
In hemorrhoids the blood falls after the stool. In fissures it lines the stools. In all other problems the blood is mixed with stools.
Hence apart from hemorrhoids and fissures which can be examined by proctoscopy ( a small instrument kept at the anal opening), the other causes may need a colonoscopy.
Please consult your PCP for primary examination followed by proper referral to a gastroenterologist/surgeon.
YOU NEED A PROFESSIONAL TO CK OUT THE COLON AND DIGESTION
IN THE MEANTIME TRY ELIMINATING ALSO TH SUGARS AND SIMPLE CARBS, WHITE BREAD PASTA ETC