Blood mucus frequent loose stools. Had sigmoidoscopy and colonoscopy with adequate view. Should I still be worried and what else can cause this?

Colonoscopy. The best person to determine what is going on is the colonoscopist. Have they not discussed the results of this with you. Usually they will biopsy randomly if there are no definitive points of abnormal mucosa visible. Call and talk to your GI doctor. Best wishes.