Flash drive files replaced with strange symbols and numbers

Hello,
I plugged my 128gb usb flash drive into my pc and a box popped up saying there was a problem with it and would I like windows to fix the problem. I clicked on 'fix problem' and after a few seconds another box popped up and said problem was fixed and flash drive was ready to use.
I clicked on the drive and opened it but all the movies and photos on the drive aren't showing and have been replaced by half a dozen files with strange symbols and numbers.
The drive is still showing 100gb is still being used so it seems the files are still there but only these strange symbols and numbers are showing. Any help would be greatly appreciated.

Phil