I'm having a problem when it comes to adding sidebar at single.php. I already included

<?php get_sidebar(); ?>

But it seems to be appear below and the content(Blog post) still at the middle of the whole page. I've tried to check all of the previous forum but none of them helped me to figure this out.

Here's my single.php

<?php
/**
 * The template for displaying all single posts.
 *
 * @package Tesseract
*/

get_header(); ?>
<div id="primary" class="full-width-page">
    <main id="main" class="site-main" role="main">

    <?php while ( have_posts() ) : the_post(); ?>

        <?php get_template_part( 'content', 'single' ); ?>

        <?php tesseract_post_nav(); ?>

        <?php
            // If comments are open or we have at least one comment, load up the comment template
            if ( comments_open() || get_comments_number() ) :
                comments_template();
            endif;
        ?>
    <?php comments_template(); ?>
    <?php endwhile; // end of the loop. ?>

    </main><!-- #main -->
</div><!-- #primary -->
<?php get_sidebar(); ?>
<?php get_footer(); ?>