If the only thing you did, was issuing the commands from the reply before, then all you have to do now is to reverse your changes as follows:
cd ~
sudo rm -R .config
mv .config.old .config
sudo shutdown -r now
Once you have done that, look if the folder is back again. If not, then just create a different user, copy their Downloads folder to your home folder and you got it back.
I actually realized now, why this didn’t work. Forgot to change the permissions of the copied folder to the home folder’s owner. Nevermind, just create another user and copy their Downloads folder. This is the easiest way.