Certainly sounds like you had a lucid dream, so congrats! That paralyzed sensation is sleep paralysis. Every night during your REM sleep periods your body paralyzes itself (this is called REM atonia) to keep you from acting out your dreams and hurting yourself. Sometimes, this happens when you are not in REM sleep, and when that happens it's called sleep paralysis. Sometimes, waking up like that from a lucid dream can cause you to end up in SP.

Just give it more time and more practice and you'll be having longer lucids in no time