it's only a lucid dream if you recognise that you are dreaming. A similar thing happened to me a while back. I was in possession of a biscuit tin that said 'open to lucidity' on the bottom but i didn't follow the instructions, and i woke up!
It does sound like your brain is recognising signs that you are dreaming, the fact that a dream character came up to you and told you you were dreaming.
If that happens again, maybe you should perform a reality check in a dream, just to test the truth of what they are saying.
By the way, welcome to the board! I know you joined a few days ago, but still, i haven't seen you before!