After I got over that sinking feeling in my stomach I searched around the web for a solution. I tried an open source solution but it did not work. I got a mess of garbage files back. After a half hour I stumbled upon Wondershare’s data recovery tool.
The software is $45. That seemed a bit steep and I wanted to be sure it would work. I installed the trial version of the Photo Recovery software and attempted to recover my images.
After setting the SD to read-only mode I mounted the card and launched the app. I selected "Raw Recovery" and was presented with a list of drives. It was easy to identify my SD card.
I selected my SD card from the list of drives and enabled the "Scan for deleted files". Then I clicked the big "Scan" button and crossed my fingers.
After about 10 minutes files started to appear. I waited until the scan was complete and selected the "nef" checkbox in the left hand pane. One click of the "Recover" button and my files were being saved to a destination folder of my choice. I was able to import these files completely into Lightroom.