Can’t get into Admin Dashboard, but I’m logged in?

SO I recently updated WordPress to the most stable, as well as all plugins and themes.

The website itself seems to be working fine.

But I can not get into the WP dashbard at all.

I’m logged in, and I can see the Admin toolbar at the top, but anything I click on, Dashboard, Menu, Themes, it all reroutes me to a 404 error page.

So I can’t manage my website at all.

What do I need to do in order to get access back to the Admin dashboard?

It seems I’ll only be able to do something via FTP since I can’t get into any WP Admin areas at all.

Thanks!

The page I need help with: [log in to see the link]