Fatal Error after installed new plugin – completely stuck

Oh, please help! I am a complete website novice. I just tried to install a Woo Commerce-related plugin. Now I’m getting the following message when I try to do anything:

Fatal error: Cannot redeclare add_local_pickup_method() (previously declared in /home/vadiaper/public_html/wp-content/plugins/woocommerce/classes/shipping/class-wc-local-pickup.php:159) in /home/vadiaper/public_html/wp-content/plugins/woocommerce-shipping-local-pickup/woocommerce-shipping-local-pickup.php on line 99

I don’t even know how to access my site now. How can I fix this when I can’t even get to my site? Please, someone point me in the right direction!

http://virginiadiapercompany.com/