You need an endoscopy and colonoscopy right away. Get a second opinion, you're being jerked around.
Mammo is right - rectal bleeding is never normal and should always be investigated until a definite cause is found. I agree that an endoscopy and colonoscopy are appropriate. Type in rectal bleeding to google or yahoo and ascertain all causes/symptoms/treatments etc so that you are better informed for your next visit to the specialist. The Medicinenet site is particularly informative.
regards
Morecambe