Can't log into admin dashboard – error received

Website http://www.AuntMonicasAttic.com was working fine last night. This morning, it just showed up as error messages (below). I was able to fix this by deleting my browser’s cookies and cache but:

I still can not access the admin panel.
I’ve tried the usual http://www.AuntMonicasAttic.com/wp-admin and http://www.AuntMonicasAttic.com/wp-admin.php. Both attempts give me the same error below.

If I type Aunt Monica’s Attic into Google, it will find the website and open it. But I get the error message below when I try to open any of the links to other parts of the webpage.

If I type in http://www.AuntMonicasAttic.com in the url search at the top of the screen, I get the error message below.
If I click on a link to my website (i.e.: from Facebook), I get the error message below.

Warning: require(inc/class-remote-notification-client.php): failed to open stream: No such file or directory in /home3/monica/public_html/wp-content/plugins/wp-product-review/inc/wppr-main.php on line 434

Warning: require(inc/class-remote-notification-client.php): failed to open stream: No such file or directory in /home3/monica/public_html/wp-content/plugins/wp-product-review/inc/wppr-main.php on line 434

Fatal error: require(): Failed opening required ‘inc/class-remote-notification-client.php’ (include_path=’.:/opt/php54/lib/php’) in /home3/monica/public_html/wp-content/plugins/wp-product-review/inc/wppr-main.php on line 434

Any help you can give me is greatly appreciated.
Thank you!