Strange repeated dream?

I get this strange repeated dream often (atleast once a month)...its exaclty the same everytime and I wake up at exact same time in the dream story everytime. The story in the dream is quite lengthy but to summarize..I have a happy life in a country side and one day...missiles are dropped all over the surroundings destroying everything..I try to escape with my family and when I hide myself behind a huge wall..thats when I wake up. The sounds of those missiles are so clear in the dream that the same sound rings in my ear all the day. And I remember the fighter planes too very well. Im finding it hard to get out of it and I will have a terrible day.

PS: I dont watch any of those war movies and I dont have sleeping or mental issues..

Why do you think this is happening and why is that I can recall only this dream and not any others.. ?