Blank pages after installing “My Category Order”

I installed My Category Order, and now all of my pages are blank. I installed based on his instructions, then went to check my categories in the admin, and they were all gone. Then I went to my blog and have the dreaded blank page, and now my dashboard is blank as well. I deleted the plugin via ftp, but the problem is still there.

https://www.masksandmakebelieve.com/blog/

Help!!! This is freaking me out!