Display NEXT and PREVIOUS pagination?

I need help on the pagination. I try to put the NEXT and PREVIOUS pagination that show the post in a same category, but I am not sure what happen that showing nothing.

If you can help, much thanks!

    div class="row"
    div class="page"
    ?php 
    $previous_post = get_previous_post('%link', 'Next post in category', TRUE);
    if ( $previous_post ) : ?

    !-- [ PREVIOUS ITEM ]--
    div class="col-xs-6"
    ?php if ( has_post_thumbnail( $previous_post-ID ) ) : ?
    ?php echo get_the_post_thumbnail( $previous_post-ID, 'gallery-navigation' ); ?
    ?php endif; ?
    a href="?php echo get_permalink( $previous_post-ID ); ?"div class="info"
    div class="info-gallery"
    h2 class="title"?php echo $previous_post-post_title; ?/h2
    /div!-- .info-content --
    /div/a!---info --

    span class="prevnext"?php _e( 'Previous Featured', ); ?/span/div
    ?php endif; //End of Previous Post Item ?

    ?php $next_post = get_next_post('%link', 'Next post in category', TRUE);
    if ( $next_post ) : ?

    !-- [ NEXT ITEM ]--
    div class="col-xs-6"
    ?php if ( has_post_thumbnail( $next_post-ID ) ) { 
    echo get_the_post_thumbnail( $next_post-ID, 'gallery-navigation' ); }?
    a href="?php echo get_permalink( $next_post-ID ); ?"div class="info"
    div class="info-gallery"
    h2 class="title"?php echo $next_post-post_title; ?/h2
    /div!-- .info-content --
    /div/a!-- -info --

    span class="prevnext"?php _e( 'Next Featured'); ?/span/div
    ?php endif; //End of Next Post Item ?

    /div
    /div