Lost all photos and videos on phone

A

AC Question

hello guys
I lost all photos and videos on my phone when i connected it via usb to PC. i did nothing wrong, i just pluged it and when i opened the DCIM folder on internal memory, there were nothing. all data disappeared and there were just two new files with no clear name and no format like ".THUMBDATA--1931678654" . but they had same capacity with my data's capacity.

what happened to my data ?
is there any way to take back my data ?