Even with blood in the stool, the odds are still against your having cancer. The majority of people with blood in the stool do on, especially at your age. And it would be very, very unlikely that you would have had cancer since the age of 12. Most people with bowel cancer are over the age of 50.

I went to the doctor over the summer with rectal bleeding, occasional loose stools (maybe once a week), some weight loss and trapped wind and the specialist said that at my age (40), the odds of cancer were very low and while it did have to be considered, it was the least likely of the options. As you are much younger than me and blood in the stool is normal for you, the odds for you are probably even lower.

I will also add the loose stools eased off for me after I had the negative colonoscopy so it is quite likely stress played a part and it may well be doing so for you too. Frequent bowel movements and loose stools can be caused by stress and the blood in the stool could ewll be piles.

You also may not have to wait that long for results. If you have a colonoscopy and it is negative, they will be able to tell you right away. I know you may have to wait for the colonoscopy, but once it is done, they should have the results immediately. If they find polyps or take biopsies, you may have to wait for the results of them all right, but again, polyps would be uncommon at your age.