Updated Plugins and Now Website & Dashboard are MISSING

I recently started updating the information on the parent and child pages of the site when I experienced a new problem this morning.

The address for the Advocacy Tab is suppose to be: https://wowinfo.org/new/advocacy/

But was appearing to be: https://wowinfo.org/new/?wlfrom=%252Fnew%252Fadvocacy%252F

Every time I went to the dashboard to “fix” the issue, I began by clicking on “Pages” at the left, then “edit”, then “Advocacy”. There, the address was correct. I clicked on the preview button and the view page button, and again, the address appeared to be fine. Then, when I logout of the dashboard to look at the site, the wrong address appeared in the url and I was unable to see the newly created page.

I was advised on a www.remarpro.com forum this afternoon to update the plugins, and then to deactivate them to see which one was causing the problem. I got as far as updating the plugins (15 in all) before I had to stop for a meeting with a client.

I just tried to open the website itself to continue working on it and was not only unable to do so, I also received this message:

Fatal error: Call to undefined function: wp() in /home/content/a/r/l/arlinford/html/new/wp-blog-header.php on line 14

Even going to the dashboard brought me this error message:

Fatal error: Call to undefined function: get_option() in /home/content/a/r/l/arlinford/html/new/wp-admin/admin.php on line 22

In summary: Not only do I not know why the website is missing, but I can’t even get onto the dashboard to examine the severity of the problem.

HELP!! This site is for a worldwide nonprofit and I can’t have it down for long!