Conflict query sorting in 2 pages

Hello,

I need to sort my post in category page, but my filter page got affected.
My filter page is a page i have created from wp backend and are using page template that has looping on it to show some post based on category filter – the page has 4 dropdown box that contain some category for filter purpose.

I just put little simple code in function.php file of my wp theme. here is the code:

add_action('pre_get_posts', 'filterByCat');
function filterByCat( $query )
{

	if( is_admin() )
	{
		return $query;
	}

	if(!is_singular()){
		if($query->is_category()){
           	 $query->set('meta_key', 'status');
        	 $query->set('orderby', 'meta_value');
                 $query->set('order', 'DESC');
		}
	 }
	return $query;

}

i use is_singular() to identify if the page rendered is not a single page, and i thought it’s enough to prevent filterByCat function executed on my filter page. but it doesn’t work. filterByCat still executed on my filter page even that page just a usual single page that using my custom page template.

Hope somebody can help me to solve this problem,
Thanks