hi, welcome to the board.
Firstly, i don't think what you are talking about is a lucid dream. it sounds to me like you are in some state of Sleep Paralysis...which can sometimes occur on coming out of a dream, lucid or non lucid.
In order for a dream to be classed as lucid, you have to know you are dreaming.
It definitely doesn't sound like a lucid dream to me, definitely sleep paralysis...it's possible you came out of a lucid dream, and then didn't remember it.
Hope this helps you out some...hope you can stick around.
For more information,you could try the attaining lucidity and lucid experience forums.
Also there's a tutorial on sleep paralysis that i wrote, being as i can induce it from a waking state.

Talk to you soon!