Why is this happening?

I was sucking in and flexing my stomach all day due to wearing a tight outfit and didn't want to look chubby
Then I started noticing a little bit of blood in the stool the next couple of days... does flexing cause the blood or is it maybe another issue?
I realize I should probably seek professional advice, but am unable to afford at this time. Hoping it will go away in a few days. If not, I will have no choice but to seek professional advice. Just wanted to see what others' opinions were....
Thank you