Sandisk Cruze = Please insert a disk into drive

I’ve had my 16G Cruse for 2 years, do a back up once every two weeks.  Put thumbdrive in usb, nothing.  Go to explorer, I see it labeled “Removable Disk”  but when I click on it to open,  get “please insert a disk into drive.”

Tried on my desktop computer, same thing.  Never had this problem.  Have I just lost all my critical data ?

Dennis