Wordpress - Recent Posts code in Header Menu breaking Post Data

I have custom code that shows the latest 2 blog posts in my site's header menu.

<?php
$recentPosts = new WP_Query();
$recentPosts->query('showposts=2');
while ($recentPosts->have_posts()) :
$recentPosts->the_post();
?>

<?php the_permalink(); ?>
<?php the_post_thumbnail_url('thumbnail'); ?>
<?php the_title(); ?>
<?php the_excerpt(); ?>

<?php endwhile; ?>

It works perfectly, except for when I view an actual blog post in Wordpress. For example, when viewing a blog post where the title is supposed to show the_title();...instead of it showing the actual post's title, it instead shows the title from the last "recent post" in the header menu.

So somehow I need to make this Recent Posts code in the header unique to itself, to where it doesn't affect data on an actual blog post page. Any ideas?

via Chebli Mohamed