permalink cause $_GET and $_POST to not work

So if I disable permalinks everything works fine. But I would rather have permalink enabled. Basically I enable permalinks with this structure, /%category%/%postname%

It creates my .htaccess file and this is it;

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

And then when I try to call $_GET or $_POST after I submit a form;

if ($_GET['numofpost']) {
	$showpost = $_GET['numofpost'];
}else{
	$showpost = 6;
}

it’s empty

Also if I do a var_dump($_GET), its empty
Is something wrong with my .htaccess file?
Thanks!