Please please someone help me

about a week ago I had a stomach bug (I believe, I had diarrhoea for a day then for the next couple of days motions were loose but improving). However for nearly a week now I have a constant feeling of “fullness”.
i don’t know if I’d describe it as incomplete evacuation because it is nearly constant and I don’t actually feel like I need to go to the toilet, it just doesn’t feel right.

im looking at booking a private colonscopy but in the meantime I am so so scared that this is rectal cancer :( I tried so hard to just get on with life as HA is constantly on my life and I feel this is punishment for ingnoring it.

Do you think the stomach bug could have aggravated down there? I’ve tried magnesium tablets and peppermint tea and nothings working I’m just getting panicky.

i also took some diazepam a week ago don’t know if that would make a difference