No, FTP is the real deal. I don’t know of anyway to undo it. I’ve had my plugins “disappear” through my WP Admin, but the folder was really there when I looked via FTP.
A lot of web hosts will have daily and weekly backups, so you may get most of your work back.
Regarding the backup plugin, it is a good idea to setup database backups to be emailed to you on a regular basis.