If during the colonoscopy
they removed a polyp or took biopsies then the bleeding could be related to this, and it can still happen up to 2 weeks after the procedure. However you should not take this lightly and contact your endoscopist for further advice.
Make sure you don't take any aspirin
, or pain medications such as ibuprofen
I would recommend you to skip work for a day, and make sure everything is ok.