Catherine Carey;Is she Henry the VIII's daughter with Mary her mother?

When I try to find out how I am related to many nobles and knights in England it all puts me through Henry the VIII even back through him then forward through him!If I am descendant of his grandmother the descent should come from her down a known path from her other children not through him to Catherine Cary!!!! I go back to many knights and nobles that I descend from in many ways and these are overlooked and I am sent down a path through Henry the VIII and Catherine Cary !!!!Is there proof Catherine Cary is Henry the VIII's if not 100% then these lines should not go through Henry the 8th!Ron Strauss