i did something wrong. I cannot access my site, editor, or anything related.

hello all,

this is a serious thing, i am not sure what i did. I was adding in the code:

function my_home_category( $query ) {
if ( $query->is_home() && $query->is_main_query() ) {
$query->set( 'cat', '123' );
}
}
add_action( 'pre_get_posts', 'my_home_category' );

to functions.php and i clicked save to see how it would work on my page, there ended up being a syntax error, and it read:

” Parse error: syntax error, unexpected T_STRING in /home1/qtiam100/public_html/wp-content/themes/spun/functions.php on line 122 “

So, I went back to erase what I put in, but the ENTIRE functions.php information was GONE, including the child theme next to it. shortly after, I was unable to access my site completely. I cannot even get into the editor without the error above showing up. Anything related to my site brings up that error. How will i be able to fix the issue if i cannot even reach the source of the problem?

please help, and many thanks in advance!!

my site