I am a 17 year old male and I have been passing some narrow stool recently. From my estimate, they are about 2cm in diameter and although they are not hard, I have to strain to pass them; sometimes I would need to go twice to completely empty my bowels, this is like half an hour later. I do not see any blood in the stools I pass.

I excercise about 25 minutes each day and I am eating slightly less than before because I wanted to lose weight.

For the past several years, my bowel movements were soft or watery and I suspect it was IBS; I had abdominal pains but this was relieved by going to the toilet. I never went to the doctor about this as I didnt believe this was anything serious and also I would have to undergo various test which I am not keen on as I am needle phobic.

Recently, watery bowel movements got less and I passed formed stool more often, but this is of the size I described above. I am quite worried about this because narrow stool can be a sign of colon cancer.

Any ideas or advice?