My jvc Everio GZ-MG155U handheld

Question

My jvc Everio GZ-MG155U handheld camera/camcorder keeps displaying-NEED TO FORMAT HARD DISK DRIVE DO YOU WANT TO FORMAT?ALL DATA WILL BE ERASED. EXECUTE OR CANCEL I have alot of footage of my children and family stored on the hdd and cant access it I did not drop-break-missuse and have checked all troubleshooting PLEASE HELP ME SOOOO SAD IF ALL DATA LOST!!!!