Dashboard Missing Posts, Pages, Plugins, Themes, etc

I logged in to my dashboard and found several modules missing including Posts, Pages, Themes, parts of Appearance. It’s also affected how the site functions. The posts are still there in the database.

I’ve disabled all the plugins except Gantry which is required for the Theme to work previously and lost even more dashboard items. I had previously deleted All in One WordPress Security which was causing issues with the site but worked fine once I deleted it.

I’ve deleted and replace wp-admin and wp-includes with no changes to the site.

I have no way to change templates as some posts suggest because I don’t have access too. This happened randomly without any changes to the site or with any obvious hacking attempts. I even created a new user name with admin rights to rule out that.

Please help as this is a production site.