Trying to show featured posts in category without duplication

Hello,

I am trying to create a category page where up to 3 posts can be ‘featured’ if they are tagged as such. I can get the first part of the posts to work properly. i.e. I can show the featured blog posts without issue.

However, when I have a more than 3 blog posts, the additional posts are not being shown by the second part of the php. I cannot figure out why, as I am sure this php worked before I upgraded to WP 3.7. Any help greatly appreciated.

<?php rewind_posts(); ?>
<?php $my_query = new WP_Query($query_string . '&tag=featured&posts_per_page=3');
while ($my_query->have_posts()) : $my_query->the_post();
$do_not_duplicate[] = $post->ID ?>

<---- Show 'featured posts here ----->

<?php if ($my_query->post_count > 3) { ?>
<?php if (have_posts()) : while (have_posts()) : the_post();
if (in_array($post->ID, $do_not_duplicate)) continue;
?>

<---- Show other posts if there are more than three in the selection ----->

<?php endwhile; else: ?>
<?php endif; ?>
<?php } ?>