"I am skeptical if data went to trash. From an external source the data is deleted without going to trash. It is always recommended to backup HDD data before partitioning it as segregating the drive shifts HDD blocks from on to another place. Get a copy of data recovery software. I would recommended either of the below:
http://www.stellarinfo.com/mac-osx-recovery.php
http://www.cleverfiles.com/
Regards"