writing

I have always had this inclination to write , I don't know why but I prefer the written word to the spoken one. This means a lot to me a written word
thereby since I am left to my own resources or am free unwillingly(read unemployed)
I took to writing a short story
Well I had the basic structure in mind everything cut out and dried I had taken up or stolen characters from somewhere but the story was my own
I started writing and then I experienced a phenomenon which I believe I have read about
Its like this my characters started taking shape of the story I was not able to direct the story according to my own wishes instead my characters started guiding the story
I had the climax all drawn and done when I had to change it because my characters wanted it differently
No I am not going nutters . In Agatha Christie books she always has this one character a Mrs Oliver who is a successful mystery writer and in one of the books she has to give sermon on how she gets her plots ad she says that its not like a story pops into my mind and I write it down its just that I see a interesting person and I delve that person into my character and then they start taking shape and they make the story
Well this exact phenomenon happened to me now my characters are giving the story a new direction and I alas am left with no means of defense instead I have to capitulate and go along their whims and fancies . And for the world of me I don't know where is my story going next..........care to help me any one?