Featured Post issue

So my site is robseipp.com
My problem here that is just rattling my brain is that the home page is perfectly fine but when you click on a post or go to another page on my site, the full post shows up. for a temporary fix, I just used css max-height to “contain” the post lol. But it would be nice to have an excerpt with a “read more” button on EVERY page/post. any suggestions? the code I’m using is this in my header
` <div id=”featuredPost” class=”post”>
<?php
$featured = new WP_Query();
$featured->query(‘showposts=1’);
while($featured->have_posts()) : $featured->the_post();
?>
<h1><a href=”<?php the_permalink() ?>”><?php the_title(); ?></a></h1>
<em class=”postMetaData”>Posted under <?php the_category(‘, ‘); ?>.</em>
<div class=”entry”>
<br /><?php the_excerpt(‘Read complete article’); ?>
</div>
<?php endwhile;?>
</div>`