Try contacting your host to see if they can restore a backup, and change your various admin passwords, database passwords and FTP passwords.
If you’re running a shared host, you should be able to perform a backup yourself through your cPanel.
What files did you replace/change?
Turns out the host backed up a week old image. Without asking me.
Lost three users, that I have no idea on how to get back. I dont remember their emails, their nicks or anything.
I suppose this actually had nothing to do with BBpress at all, but my host instead.
I got them to restore a newer backup now so everything is okay again.
Though this all got me thinking what BBpress could offer to protect against this sort of thing. I know you can back up SQL bases in Cpanel, but maybe you could make a backup file of the users in the adminpanel of BBpress?
Lets say there was a risk of loosing something, you could back up your users, and if you lost some, you could restore their accounts with ease.