Hiya - I'm going through a similar thing at the moment and I know how scary it is so I sympathise.

Firstly I'll say that considering your age it is incredibly unlikely to be cancer and I would imagine the blood is more likely due to the hemmorhoid, although it's definitely still important to get it checked out, especially considering the darker blood. If you have a large hemmorhoid, it's possible that that's causing an obstruction which could cause the ribbon stools. It's also possible that it's IBS or IBD. I would really push for a stool sample and blood test if they don't readily offer them.

Secondly - would it be possible for you to see a different doctor? At GP surgeries you're usually assigned a certain doctor, but are still able to request to speak to a different one. I was getting nowhere with mine & instead specifically called and asked for a female doctor (which is not a guarantee, but in my experience male doctors have a higher likelihood of being condescending & dismissive towards female patients) and she's been great and immediately put me through to lots of testing. Any doctor that dissmises issues as being due to your weight isn't a good doctor to work with and could be missing underlying factors - you deserve to talk to someone who respects and listens to you!

Hi,

If your doctor dismisses you please request to see another one or if not possible change DRs. Yes, due to

 your age it is unlikely that it is bowel cancer. However, the simple fact that you have written on here tells me you know something isn't right and you are concerned. Never allow a health profession to dismiss your concerns or symptoms. You are the only one that lives in your body so you are best placed to decide what needs further action. A few years ago my best friend died of bowel cancer. She was 32, but we can remember her complaining about what we now know as symptoms from as young as early 20's. She fought for years to get diagnosed and in the end she was too late. Her Dr litterally called her a hypochondriac in the end....she was dead around 10 months later. A very simple effective way for them to rule this out is by doing a colonoscopy.

Please, please, please insist on having one. My Aunty also passed away last week with bowel cancer she was 54, again went to Dr years ago they gave her an ultrasound on her ovaries said she was fine. Five years later after persistent niggles a further test revealed stage 4 bowel cancer. It appears it's hard to get DRs to take this serioustly due to the age brackets. So please fight for yourself. I don't want to scare you I just want to highlight to keep pushing for answers for yourself. Sending you lots of love, Marina x