The odds are you don't have bowel cancer, especially if your doctor isn't worried. I had similar symptoms last summer (except they didn't find any sign of hemorrhoids when I went to the doctor; it did turn out I had them though). I had numerous weeks of blood on wiping and had lost maybe half a stone to a stone of weight in a year or less. I then started getting loose stools and later started getting trapped wind.

When I finally saw a specialist, he said that at my age (I was 40 at the time), the odds of bowel cancer were extremely low and I would be "the unluckiest person in the world" if it turned out to be that. They did find hemorrhoids in the colonoscopy and they almost certainly caused the bleeding. The other symptoms were probably a combination of the stress of the whole thing and a few coincidences. 

Your age is relevant here too. He said if my mother were to come in with the same symptoms he would be considering bowel cancer as a possibility, but at 40, it was highly unlikely. Given that they found hemorrhoids which probably explain the bleeding and that the changes to your bowel habits started afterwards, when stress could play a part, I think the odds are good that things are OK with you.

I know how worrying it is to have bowel cancer (or any form of cancer) suggested as a possibility at all, but there are many reasons for the symptoms you are experience and cancer is probably nowhere the most likely.

Thank you for your reply. I am 43. No family history of bowel cancer in the family but plenty of other forms sadly. Dr Google is never a good idea either but I can't seem to stop myself. Every little thing I am putting it down  to something scary. The thought of being like this for 3 to 4 weeks and then having to start the process is hard. I want it now so if it is serious I can start to fight it. I am just constantly thinking about it. I hate how I'm feeling currently.