I died in my dreams. what does it mean?

I've had many dreams where I came close to seeing myself die but I would wake up before it happened. Last night I died in my dream. I was in an elevator and if fell 4 floors and it was so real and I remember thinking I'm going to die. Then I was dead and I crawled out from under the rubble and it was an open space of land and one person was standing there waiting for me dressed in black. ARGHHHH!!! Scary. On September 11th in the middle of the night I had a dream that I died in a plane crash but woke up before we crashed. It was about 2:00 am the morning the towers in NY came down. I also had a dream there was a huge earthquake and I couldn't sleep the rest of the night. This was the night before the big Japan earthquake and tsunami. I hope my dream last night doesn't mean something bad in real life.