Being hacked from this ip 91.224.160.35

The IP belongs to a known WP hacker. Block all access to it in your .htaccess file. Either add the following or edit something similar already there to the same effect.

<Limit GET POST PUT>
  Order Allow,Deny
  Allow from all
  Deny from 91.224.160.35
  # add more 'Deny from' lines to block more bad IPs
</Limit>

I’ve never seen a message like yours before, I’m guessing your host put it up as a load limiting and/or security measure. If so, you probably need to log in to your hosting control panel to release the lock.

While shutting down your site is an extreme measure, it may have prevented your site from actually being hacked.

You also need to start working your way through these resources:
https://codex.www.ads-software.com/FAQ_My_site_was_hacked
https://www.ads-software.com/support/topic/268083#post-1065779
https://smackdown.blogsblogsblogs.com/2008/06/24/how-to-completely-clean-your-hacked-wordpress-installation/
https://ottopress.com/2009/hacked-wordpress-backdoors/

Additional Resources:
https://sitecheck.sucuri.net/scanner/
https://www.unmaskparasites.com/
https://blog.sucuri.net/2012/03/wordpress-understanding-its-true-vulnerability.html

Don’t know how, but I managed to enter my site and immediately banned this IP. Also I have activated IP black list from the plugin “Better WP Security” as more of its anti-hack functions.
Nevertheless, thank you guys for your kind attention, wish you happy hours!!