WordPress Admin running incredibly slow

Basically the title says it all. Front end of the sites are fine but doing anything in the admin is impossible. Also, after this problem started in the last day or two, I created a new site which is now giving me a “you must enable cookies” error and won’t let me log in.

The problem is similar to here: https://wordpress.org/support/topic/woocommerce-extremely-slow-after-wordpress-42-update?replies=60

But it started before I began to add in Woocommerce. Yes, I’ve disabled and re-enabled my plugins (which never fixes anything to everyone who suggests that) and I’ve tried disabling and re-enabling the new site.

Doing any admin work on my site is effectively dead and I’ve spent two days working on this which seems to be a WordPress problem at this point. Anyone else having this problem and have any solutions for it?