examination of the bum

im a 21 year old female. for the past month i have had blood in my stools its been in my stools often, its in the toilet bowl and on the tissue, really bright red in colour too and the blood in the toilet bowl seems to be a very dark bloody colour. i been to the doctor and he said it could be hemrroids so he gave me some cream to use for 2 weeks and its now gone 3 weeks but the cream still hasnt stopped the bleeding. i have also been feeling very drained and seem to be sleeping alot more, i have stomache pains often and its painful, shortness of breath, and i been having runny poo (an upset stomache) evry couple of weeks. my poo is usually broken up into pieces. so i have looked online and seen some stuff that i didnt want to see, my symptoms seem to match colon cancer, am i too young to have colon cancer? and colon cancer does not run in my family at all. but something inside of me is saying something is wrong like a gut feeling, but i dont want to seem stupid to the doctor as i know he will say your too young for bowl cancer as thats what most people think. the doctor said if the bleeding dont stop i have to go back for an examination. what will this examination be? and im really scared that i do have colon cancer. it would be more than helpful to answer this if you have ever had colon cancer or are suffering now as i need some advice from someone who has been through it and can tell me if this sounds like colon cancer, im also so embarassed to have my bum messed around with by a doctor so its holding me back from visiting him again.