Comment system issue - php

Question

I have a problem with my comment system. At the moment it is just simple adding to database sorting and showing under right post on the blog. I am creating, I will implement ajax etc later.
The issue I am having right now is that it shows the last comment on the post below the one I added comment on. So lets say I am adding comment on post 10, it will show comment on post 10 and 11. It sorts correctly, but it duplicates to the post below too. (It doesn't duplicate in database just the way it displays.)
<?php
// Connect to the database
include('../acp/db/db.php');
$link = mysql_connect($dbhost, $dbuser, $dbpassword, $dbname);
mysql_select_db($dbname);
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$result = mysql_query('SELECT * FROM `posts` ORDER BY id DESC') or die(mysql_error());
while($row = mysql_fetch_array($result)) {
$id_post = $row['id'];
echo " <!-- Blog Post Content Column -->
<h1> " . $row['post_title'] . " </h1><p class='lead'>
by <a href='#'>Matt</a></p> <hr>
<p><span class='glyphicon glyphicon-time'>" . $row['date_created'] . "</span></p>
<img class='img-responsive' style='width: 900px;height: 300px;' src=" . $row['post_img'] . "> <hr>
<p class='lead'>" . $row['post_first'] . "</p>
<p>" . $row['post_second'] . "</p> <hr>
<!-- Comments Form -->
<div class='well'>
<h4>Leave a Comment:</h4>
<form id='form'method='POST'action='php/insert-comment.php'>
<input type='hidden' name='post_id' value='$id_post'>
<input type='text' id='comment-name' name='name' placeholder='Your name' />
<input type='text' id='comment-mail' name='mail' placeholder='Your e-mail adress' />
<textarea type='text' name='comment' class='the-new-com' rows='3'></textarea>
<input type='submit' id='submit' class='bt-add-com' value='Submit Comment'></input>
</form>
</div>
<hr>
<div class='media comment-block'>
<a class='pull-left' href='#'>
<img class='media-object' src=' $grav_url' >
</a>
<div class='media-body'>$name
<h4 class='media-heading'>
<small>$date</small>
</h4>
$comment
</div>
</div>";
$resultcomments = mysql_query("SELECT * FROM `comment` WHERE post_id = '$id_post'") or die(mysql_error());
while($affcom = mysql_fetch_assoc($resultcomments)){
$name = $affcom['name'];
$email = $affcom['mail'];
$comment = $affcom['comment'];
$date = $affcom['date'];
$default = "mm";
$size = 35;
$grav_url = "http://www.gravatar.com/avatar/".md5(strtolower(trim($email)))."?d=".$default."&s=".$size;
echo"
<!-- Posted Comments -->
<!-- Comment -->
<div class='media comment-block'>
<a class='pull-left' href='#'>
<img class='media-object' src=' $grav_url' >
</a>
<div class='media-body'>$name
<h4 class='media-heading'>
<small>$date</small>
</h4>
$comment
</div>
</div>";
}
}
?>
I am slowly learning PHP so be easy on me. I feel like the issue is easy to fix, and it is right there I just cannot work out what it is.