WD MY BOOK ESSENTIAL 1TB

HI, I'VE HAD MY WD MY BOOK ESSENTIAL 1TB FOR ABOUT THREE MONTHS AND HAD STORED A LOT OF INFO. ONE DAY I CAME HOME FROM WORK AND A MEESSAGE WAS ON MY SCREEN THAT READ THAT IF I WANTED TO FORMAT MY DRIVE.... I PRESSED CANCELED AND TRIED TO ACCESS MY DRIVE AND WHEN I CLICKED ON IT IT ASKED AGAIN IF WANTED TO FORMAT IT. HOW CAN I FIX MY DRIVE OR RECOVER MY INFO. THANKS