Site and admin disappeared

My site is shonnielavender.com/blog

I created a new post, backdated it (to show up a few days previously), and published. When I went to view the post, nothing showed up. The page title showed up as the URL instead of the actual page/post title too. I’ve had no other problems with the site in the last year. Then I saw that one of my plugins–“Similar Posts”–wasn’t working on some posts, including in the “preview” version of my newly created post. So I deactivate that plugin and another similar one (contextual related posts). Now my entire site is inaccessible — I can go to the login URL, but nothing shows up, no error message, nothing. Just the URL as the page title and a blank white screen.

Any good advice on resolving this issue and getting my site up and running is much appreciated. Thank you.