Cannot access control panel

[Tymoteusz]

Hi, I've installed wordpress into website (seen basic template and wanted to do everything else next day) yesterday and everything was fine till today when I woke up and tried to do more and it couldn't let me into control panel and even on my site Error establishing a database connection appears (can't access wp-admin). Anybody knows smth about it? In a shortcut I'm stuck at the services page and cannot do anything else