recovering hidden attributes on external hd

I had bought an 1TB external hard drive inwhich I stored all my CPU files on.. noticed something was missing so I went to the properties of that Main folder. I clicked Hidden Files on the attributes part thinking it might be as a hidden folder, next thing i know my MAIN folder is missing! so how to I recover it back??.. My drive says theres still something there since its showing that something is taking up the same amount of space as the main folder of 52Gb