The story (Judges 13-16) goes on to tell us that when Samson's hair was cut off, surely enough he lost his physical strength. His faith in his good deeds failed when his good deeds failed. Uh-oh. In a last ditch effort to get his strength back, Samson turns to God and simply asks for it. And then he acts, in faith, hoping against all hope that his strength would return - and what do you know? He pushes against two pillars and brings the walls crashing down!!!
Your strength is not in being a Nazirite or a Christian. It is not in your good deeds (long hair never shaven might equate these days to some other physical act, like being sexually perfect or something). Your power comes from God who lives inside you. And even when you fail (in deeds) and your hair get's cut off or you're accused of not really being a Christian, keep believing! The power within you is greater than the power of any good deeds or religious labels.
You have the power within you for greatness!