google webmaster tools , need to re verify my site

i have been using googles webmaster tools for just over a month now , and i think they are very good , but just now i logged in and my site had basically gone , it says i need to verify again , why the hell do i need to do it again , has anybody else had to do this

 

Resubmit once again and after getting code, upload this code in your site in between head and body