Server not found and can't access wp-admin

Hi,

URL: http://www.yummymummyphysio.com.au

Site had been working perfectly last few weeks and suddenly its not working.

URL now turns to this URL: http://yummymummyphysio.com.au/wp-admin/install.php – displaying the WordPress install page, asking for Information needed to install.

I don’t understand why it’s asking to install WP again.

When I try to access my dashboard – http://www.yummymummyphysio.com.au/wp-login.php – the URL goes funny, changes to this: http://yummymummyphyummymummyphysio.com.au/wp-login.php
with a message saying server not found.

I have tried to delete child theme and plugins in case these files were corrupted, but it made no difference. I’m wondering if it’s got something to do with the DB details, but I’m not sure, and I don’t understand why it was working perfectly for weeks and then stopped working.

Please help!
Thanks