What does my dream mean?

I've had dreams where I see catastrophic Apocalypses. There was a flooding of a river which was the Mississippi recently... but it happened after my dream, as well as several dreams of tornadoes touching down on the flat plains and in the city. Which actually happened in the Mideast U.S. and in California months after my dream... Another was a tsunami flooding a city which I had to get away from and I was in Asia, going up a hill to a house with the oriental looking sloped roofs, months ago before the Japan Tsunami. I've had one that's been on my mind every time which was a huge ball of fire coming down from the sky which hit a side of a gray mountain sending ash towards me and that's where I died in my dream. I've had this dream a year ago. It still worries me today every time I think about it, I get the chills. What does all this mean?