It's very common to have dreams with nasty creatures coming after you; they often represent anxieties that you are facing in waking life, the fact that you made it go away with your Hail Marys shows that you have the strength to face up to the things that are bothering you and make them go away.

See also the dream dictionary on Werewolf but don't dwell on it too much, like I said, you made it go away so that is a very positive sign.