Yes, you must participate in the blood ritual to continue. However, your given the opportunity to cure your Lycanthropy during a later quest (warning: this quest may be glitched, as quite a few people are unable to rid themselves of this disease). Aela will return to normal after your next quest or two, I can't recall exactly what happens. I do know that after Glory of the Dead is over, all Companions are available for training, as well as followers/spouses.