automated WordPress update has failed,Plugin install failed.500 fatal Error

Hey Everyone.

I am in the panic mode….

I am running since 8 month a blog with wordpress. http://www.luxuryworld360.com
Since some days i am facing some serious issues.

All the sudden my yoast Seo tool vanished. Non of my post has anymore keyword or description tag. Yoast Seo is not installed anymore. By trying to install the plugin again, it shows> plugin install failures.

I also get the message at the dashboard that my automated wordpress update has failed.

When i try to install certain plugin the website crashes complexly.
Fatal Error 500.

I am ready to upgrade to a premium wordpress account if that would help somehow. But i am not sure if my data will get lost, by upgrading.

No Idea if the are problems by Godaddy where my Website is hosted. I wish i could call someone from WordPress to get help!!

Thanks for your comments in advance.

Very best Johanne s