In your case, you need to try a USB hard drive recovery freeware to regain your data. Actually, this freeware has ever recover my inaccessible data from a corrupted drive successfully. It won't let you down! Note for you:
1. Stop writing anything new on the same drive to avoid original data overwritten by new data, which can make your data gone permanently.
2. Save your recovered data on a different drive in case of recovery failure.
3. Not forget to format this drive to see whether it could work.
4. Back up your data regularly in the future.