Using PHP Value with GET clause

We are using the get clause to attempt to get the current 'upload_link' to be placed in the pop up video player.

however we're ruing into issues of it saying our values are undefined, and will not out put the GET values into the URL. All changes are taking place on the same page, any suggestions on a better way to pass the values welcomed as well.

HTML

<body>
<?php
include_once('includes/top_db_conx.php');  
$Youtube->upload_link = $_GET['upload_link'];
if ($row['upload_link'] == ""){
    echo $row['upload_link'] = "G8KpPw303PY";
}else {
$swapID = $row['upload_link'];
}
?>
<?php 

while($row = $stmt->fetch(PDO::FETCH_ASSOC)){

    ?>

<div class="video_bg" id="popupVid" style="position:absolute;left:0px;top:0px;width:100%;height:100vh;height:auto;display:none;z-index:200;">
   <iframe width="100%" height="auto" src="http://www.youtube.com/embed/<?php echo $swapID; ?>?enablejsapi=1&rel=0&controls=0&showinfo=0&modestbranding=1&fs=0" frameborder="0" allowfullscreen></iframe>
   <br /><br />
    <div class="play-bottom">
   <a href="javascript:;" onClick="toggleVideo('hide');" class="tog">close</a>
    </div>
    </div>


  <div class="element img-box tog">
      <a href="javascript:;" onClick="toggleVideo();"> <img class="switch" src="http://img.youtube.com/vi/<?php echo $row['upload_link']; ?>/0.jpg" alt="placeholder"></a>
        <div class="bottom-box">
       <div class="bottom-content">
            <h2 class="bottom-tittle ellipsis overflow"><?php echo $row['title']; ?></h2>
            <span class="date"><?php echo $row['upload_date']; ?></span>
       </div> 
        <div class="like-box">
            <i class="fa fa-heart-o"></i>
            <span><?php //echo $row['numLikes'];?>0</span>
            </div>
    </div>
  </div> 


</div> <!-- #container -->

DB coections

ini_set('error_reporting', E_ALL);
    //exteal pages area
    include_once('config/database.php');
    //include_once('object/flickr.php');
    include_once('object/youtube.php');
    //include_once('bottom_db_conx_close.php');
    //grabs info from the various pages.sql files
    $database = new Database();
    $co = $database->getCoection();
    $Youtube = new Youtube($co);
    //$Flickr = new Flickr($co);
    //coection made with sql file
    $stmt = $Youtube->readAll();
    //$stmt = $Flickr->readAll();
    //reading all the data in the sql file
    //echo ('database, coected');
   // echo $Youtube('vid_id');

Current Errors

Notice: Undefined index: upload_link in

/home1/site/public_html/folder/index.php on line 18

Notice: Undefined variable: row in /home1/site/public_html/folder/index.php on line 19