Files not showing up in USB drive

Hoping someone can help. I've done several searches online and also searched the forum for something similar.

I have a Macbook and had a USB drive plugged in. I closed it to let it go to sleep and thought it would be okay to take the drive out. However the next morning when I opened it, it said the device wasn't removed properly. Now when I plug it in I can't find the folder that I was using before. It is still taking up space in there though, because there are less than 2GB free, as before.

I've also plugged the drive into a PC and had the same problem.

Any ideas? I've run Disk Utility on it but nothing changed. I verified it and there was an error, so I repaired it and verified it again. Still no folder.

Thanks!

Hello,
You can try Data Rescue.