Yikes. I just saw this and since it was op 3 days ago I hope the dog is okay? Dogs can have a little blood and mucus in loose stools just from stress but "bloody diarrhea all over the family room" sounds serious. Research HGE
Hemorrhagic Gastroenteritis (HGE): A Cause of Bloody Diarrhea in Dogs
Hope that was not the case, difficult to diagnose but immediate treatment is important. Let us know how your dog is!