Error establishing a database connection And PHPmyAdmin Not Working

Title says it all, The website was working perfectly this evening and now when i try access it it says “Error establishing a database connection”. I checked my wp-config but all the settings are the same as before. Did I mention PHPmyAdmin isn’t working either?

So if any one could be of any help, that would be great, since I’m kinda scared(although i ahv a backup of both db and website, recent too, but common, it takes forever to upload the site with filezilla!)