I've found that my experiences with lucid dreaming are like this. Let me explain: whenever I'm inside a dream, and I decide to RC, I become lucid. I then proceed to get overly excited (which can make the dream unstable.) I start touching things, trying to anchor myself in the dream. But, I cannot stop my mind from thinking: "Wow! This is a dream! Don't wake up! Don't wake up!" And this ultimately leads to me waking up within a few seconds of becoming lucid.

So, back to the title: "You know when you're trying not to think of something but you can't get it out of your head?" - Well, that "thing" that I am trying not to think of is waking up, which inevitably happens whenever I try to get that out of my head.

It's just like that Inception quote about the White Elephant.

This might be sort of vague, but any help/comments would be appreciated here.