Snot like stool, is that mucus? Also burning

I have a colonoscopy on Aug 5th. I am fairly sure I have IBS because no blood in stool at all. But last night I felt the urge to have diarrhea and I only pooped a small amount and it was a yellowish brown and looked like snot, is that mucus????

Also, does anyone else get burning when they go to the bathroom like they ate something spicy but they didn’t?

Also, what did you eat the most of when you were prepping for the colonoscopy? I’m seriously worried about the prepping because I already get chronic diarrhea, should I buy like distort rash cream or anything? Thank you!