It seems that your drive is corrupted.
If you still want to get back your data inside this hard drive, I would recommend you to try a free drive recovery tool
, which has helped many people retrieve their photos, videos, music and files from a "not formatted" drive, including me. It is worth trying!
You also should attention to some tips
1. Stop writing anything new on this drive immediately to avoid the original data overwritten by new data, which can make your data gone permanently.
2. Save your recovered data on a different drive or memory card in case of recovery failure.
3. Not forget to format this drive to see whether it could work normally as before. Otherwise, you have to buy a new one to replace it.
4. Back up your data regularly in the future.