form button deleting data by clicking it

My web page is a forum where users can post text and images, then have them displayed on the web page. There is a like and dislike button that is output with each post. Everything works fine except when I hit the like or dislike button the post deletes itself; however, the likes are saved in my database, so I can tell there’s nothing wrong with my queries, so is there something wrong with my form?

Here it is,

//not full file
            if (isset($_GET['postid'])) 
            {

                if (!connect::query('SELECT post_id FROM dry_likes WHERE post_id=:postid', array(':postid'=>$_GET['postid']))) 
                {
                       connect::query('UPDATE dry_posts SET likes=likes+1 WHERE id=:postid', array(':postid'=>$_GET['postid']));
                       connect::query('INSERT INTO dry_likes VALUES (null, :postid)', array(':postid'=>$_GET['postid']));
                } 



                if (!connect::query('SELECT post_id FROM dry_dislikes WHERE post_id=:postid', array(':postid'=>$_GET['postid']))) 
                {
                       connect::query('UPDATE dry_posts SET dislikes=dislikes+1 WHERE id=:postid', array(':postid'=>$_GET['postid']));
                       connect::query('INSERT INTO dry_dislikes VALUES (null, :postid)', array(':postid'=>$_GET['postid']));
                } 

            }


            $dbposts = connect::query('SELECT * FROM dry_posts ORDER BY id DESC');
            $posts = "";

            foreach($dbposts as $p){
                    if (!connect::query('SELECT post_id FROM dry_likes WHERE post_id=:postid', array(':postid'=>$p['id']))&&!connect::query('SELECT post_id FROM dry_dislikes WHERE post_id=:postid', array(':postid'=>$p['id']))) {
                            $posts .="<img src='".$p['postimg']."'>".htmlspecialchars($p['body'])."
                            <form action='try.php?postid=".$p['id']."' method='post'>
                                    <input type='submit' name='like' value='Like'>
                                    <span>".$p['likes']." likes</span>
                                    <input type='submit' name='dislike' value='Dislike'>
                                    <span>".$p['dislikes']." dislikes</span>
                            </form>
                            <hr /></br />
                            ";

                    } 

            }

Here’s the form

<form action='try.php' class = "forum" method="post" enctype="multipart/form-data">
<textarea name="postbody" rows="4" cols="60" class = "text">

</textarea>
         <br />Upload an image:
        <input type="file" name="postimg">
        <input type="submit" name="post" value="Post">
</form>


Source: stackoverflow-php