I would ask your GP for a stool test to check for intestinal inflammation (fecal calprotectin), and a stool test to look for pathogenic causes to your symptoms. If you can prove you have intestinal inflammation and that it is NOT an infection then a gasteroenterologist-specialist would be more compelled to give you a colonoscopy for investigation for IBD/UC/crohn's.
A lot of blood in stool is a calling card for UC.
You could have IBS or an intestinal-motility issue (muscle movement).
Hard to say, you need some labwork and a colonoscopy.
There are a few IBD lab tests based on only bloodwork, pretty new and not used solo for diagnosis, but a possible plus if you need more evidence to investigate further. Take a look at Prometheus Labs and you'll see the tests I'm talking about
Moderator Ulcerative Colitis
John, 40, UC Proctosigmoiditis
Rx: Remicade @5mgs/kg/6wks; daily 75mgs 6MP, 4.8g generic-Lialda, and rowasaIs it unpatriotic to wipe your bumm with George Washington bills if there's no tp in a stall and you're otherwise in dire-straights? I think George would understand...