Trashed songs are not gone. They go to the Trash smart folder in your library.

 

On iPhone, iPad, and Android, tap Trash, find the song, and put it back. On Mac and Windows, click Trash, then drag the song back to your song library or straight onto a playlist. You can also right-click the song and choose Restore Song.

 

A deleted playlist cannot be recovered, although its songs can. If you are about to try something drastic, duplicate the playlist first.

 

For more, see Organize your songs into playlists on the iReal Pro website.