@Rebeccasayer: Nah lucid dreaming is when you can control your dreams and do what you want. When you feel like someone is sitting on you or something like that, that means you are extremely stressed, you're having a panic attack, and it's happening during your sleep. This is where the word "nightmare" originates from. It's folklore/mythology. The "mare" was a creature that would ride on your chest at night and fill you with anxiety. Hence, the nightmare. Read a bit about it. It's interesting.