over lockdown I noticed I was constantly having diarrhoea and I haven't passed a normal stool in around 6 months now, I went to the doctors 3 months ago and they did an urgent cancer referral for a colonoscopy.

when I had the colonoscopy they weren't able to get past the colon to view the bowel but wouldn't say why so it was classed as a failed colonoscopy yet they did say they noticed blood in the bowel but couldn't get to it. 
I have a CT in 3 weeks to allow them to see my bowel due to the failed colonoscopy and I've now noticed a lump in my lower left side of the abdomen under the skin.

does anyone have any ideas of what this could be? My mind keeps going to cancer but I'm trying to think of other things it could be. I've also been bleeding when going to the toilet.