AVCHD movie file converted to file folder

I plugged in the SD card from my Sony Handycam, and then renamed a AVCHD movie file. When I did that, it immediately converted to a file folder, and now the actual movie file is no longer there. I cannot find it, and I cannot find any help online on how to recover this movie file or convert it back to the movie file. The 'file folder' is still the same size as the movie file was, so I think it's there somewhere, but it seems I may need to convert this folder back to an actual AVCHD movie file. How do I do that? I'm running the latest OS X.

Thank you in advance.