FreeAgent Go Flex External suddenly showing 0 items on my macbook

The other day I was mixing an album on Pro Tools when suddenly my macbook completely froze. The usual please restart didn't even come up, it was just frozen and I could not eject my external hard drive or shut down pro tools or even my macbook. After a little while I finally did hold down the button long enough to shut it down, but when I plugged in my external the next day, 0 items showed up. I suspect that the data I had on my external might still be there cause it says 461 GB available and it's a 500 GB hard drive. Is there a way to access these files? Also important to note is that I don't know if I ever formatted it correctly because I did have problems transferring between PC and Mac. But I haven't had problems opening my Pro tools sessions from it. Lastly when I did check it says it's formatted NFTS for Windows. I'm not very hardware savvy, but hopefully that explains it enough.