Is it possible to restore songs (not purchased through itunes) erased from a device by itunes sync?

I recently had to reinstall itunes after all of my computer files were completely lost. When I plugged my iphone into itunes and attempted to transfer my music from the phone to the computer (running windows 8.1), itunes erased all of my music that was not purchased through apple (and also ruined my playlists). Because the files on my computer were all lost, i do not have this music backed up anywhere.

I was wondering if there was any way to recover all of the songs that itunes had erased from my phone.

This really is quite frustrating because the deleted songs arent even available on itunes itself for purchase!