What do you think about when you can't fall asleep?

I think about Heaven. What it's like there and what it would be like if it didn't exist. What if after death there is nothing. What if after death, your existence just stops. No reincarnation or life after death. I believe Heaven exists, but what if I'm wrong? That's just one of the many mysteries I think about. Or what if Reincarnation exists, and your life, the people you love, the social status you hold, just disappears from your memory in your next life. Your parents, teachers, uncles, aunts, friends will all be forgotten in your next life and be replaced by new people. Thinking about it scares me.

I also wonder if everything, this world, it's people, it's animals and plants, are all part of my imagination. What if I'm an alien in another world, asleep and dreaming of a little boy, Justin Cruz. What if this world is something like a movie for an advanced civilization. An advanced force created and is being entertained by us. We are no more than imaginary creatures given artificial intelligence. A TV show.

I know I sound wierd, but that's what I think about when I can't sleep. Stuff like that just pops into my mind.