My htc one max just deleted everything

[Dogfish666]

My phone, over the course of about an hour deleted every single file on my SD card, one by one. I cannot figure out why I am panicking and pulling my hair out. It's on stock htc android with sense, jellybean. I want to know what on earth has happened to all my files, my photographs, everything. And maybe if there is a way to restore my data and continue using this phone because right now I just want to snap it in half to save me the heartache of this ever happening again.