I've had apocalyptic dreams in the past... and some have come true, and some have not. The fear of nuclear war is so deeply ingrained in our culture now that we do not even acknowledge it's presence any more - but I remember waking up in the late 1970s and early 1980s, listening to planes going overhead, wondering if those were the bombers that would wipe us out.
I have dreamed of stellar fire crawling across the face of the planet, as the dying gasp of a distant nova brings us finally to peace with each other in the only way we ever could be in this world.
I have watched in my dreams as ebola spread around the globe and people coughed their last as their intestinal linings detached and slid out their rectums.
I have seen the light of the atom as it flashes from a point and expands to fill a whole city, leaving dust behind it.
I have witnessed the last moments of earth as it begins its slow slide down the gullet of a starving black hole.
Ever watch "The End of Evangelion?" When I was a kid, I had dreams like that - where some kind of Revelation happened - and the bodies of people all over the world dissolved, leaving only their souls behind. Instead of angelic light, though, all that was left were the hideous monsters we all hide, and they all tore the few good souls into oblivion, leaving the world Hell.
I've had dreams of planes crashing for years. I've been on a few of those planes in my dreams. Sometimes they crash into buildings, sometimes the ground, sometimes water. Sometimes it happens right before a plane crash, and I have this weird feeling afterwards, but it goes away after a while - generally about the same time I have my next plane crash dream, and realize that it felt the same.
I cannot count the number of ways I have watched the world end in my dreams. But remember, dreams are a reflection of what you see in the world around you. When 9/11 happened, can you say that you had not somewhere inside of yourself expected something like this some day? I know I have been expecting some kind of escalation by SOMEBODY for years now - and I have been telling people that as well.
Do not be surprised by our capacity to be cruel to each other. Imagine the worst you can, and if you can imagine it, somebody else might be thinking about doing it.
Do not be surprised by the Random Number Generator in your head - if everybody, or a good portion of everybody had the same dream, then yes, that would indeed be one Hell of a coincidence. But if it's just you, or a couple people, then more likely than not it is one of those coincidence things that keep happening.
Your dream might be a prophecy. It also might be one of the most advanced analytical engines on this planet taking events as it sees them and speculating as towards future events, and then filtering it through to your consciousness in a way that it might be able to understand the events and take action to end them.
Do not let dreams ruin your life - I have struggled with mine, and I know them now for what they are. Warnings, yes, prophecy, most likely not.