WordPress deleted Database Tables on its own

Hi everyone!

I setup a wordpress-site a few weeks ago and there was a lot of work that went into it. It still worked yesterday, and without me even doing anything on my site, when I visited it “Error establishing a database connection” appeared.
I tried to “Repair & Optimize” my database, but the only thing it did is give me these errors:

wp_users: Table 'db84650x1991405.wp_users' doesn't exist
wp_usermeta: Table 'db84650x1991405.wp_usermeta' doesn't exist
wp_posts: Table 'db84650x1991405.wp_posts' doesn't exist
wp_postmeta: Table 'db84650x1991405.wp_postmeta' doesn't exist
wp_terms: Table 'db84650x1991405.wp_terms' doesn't exist
wp_term_taxonomy: Table 'db84650x1991405.wp_term_taxonomy' doesn't exist
wp_term_relationships: Table 'db84650x1991405.wp_term_relationships' doesn't exist

I also checked in PHP-MY-ADMIN, and the tables are really not there. It′s especially annoying because the wp_posts-Table contains all the text written.

Unfortunately my hosting-provider does not do backups for the databases, so my question is if there is anything I could try to get the missing tables back – and what could′ve caused this?

Thanks in advance,
Vincens