Formatted external drive

I have an external drive I've been using from new with my 2012 macbook pro. I recently put all my work files on it as my macbook was dying(only powering on for a few minutes at a time)

I connected it to a Windows laptop and formatted the drive whilst trying to view the files on Windows machine, not realising I would lose all my files.

The drive hasn't been used at all since formatting it.

What steps should I take to recover the files.

Any help would be greatly appreciated as it contains a lot of work that hasn't been backed up anywhere else and the macbook pro is only powering on for about a minute at a time.

I would really appreciate any help.

Kirsten