Newbie – Fatal Error

Hi, I am very very new to WordPress. So if I need to hire someone to do this, then I’d be glad to do that too. I just don’t know where to go to get a webmasters help for this one issue. Here’s my issue: I installed the woocommerce plug in, and it made my wordpress really slow. So, I deleted woocommerce and got a fatal error. Now I cant log into wordpress. I just figured out how to access my file manager through cpanel. I found the file that is referred to in the fatal error:
Fatal error: Call to undefined function is_shop() in /home/vrwlacqa/public_html/wp-content/themes/TESSERACT/woocommerce/woocommerce-functions.php on line 7

but i don’t know what to do about that line.
this is line 7 of my woocommerce-functions.php file-
$isloop = ( is_shop() || is_product_category() || is_product_tag() ) ? true : false;

do i need to take something out or replace something ? and then once i do that do i delete the woocommerce-functions.php file and upload my new one with the changes?

I really want to be able to install and use the woocommerce plug in on my site.