PHP - Time Ago Function

Hello. I'm trying to create a function that will turn my timestamp into something like "9 hours ago", "3 days ago", ect.. so far I have the below function which seems to do the job fine. only problem is when i try to include it within a span it always places itself right before it.

I use
Code: [Select]
echo "<span class=\"smalltext\">".time_stamp($date)."</span>";
witht the following function
Code: [Select]
function time_stamp($session_time)
{
$time_difference = time() - $session_time ;

$seconds = $time_difference ;
$minutes = round($time_difference / 60 );
$hours = round($time_difference / 3600 );
$days = round($time_difference / 86400 );
$weeks = round($time_difference / 604800 );
$months = round($time_difference / 2419200 );
$years = round($time_difference / 29030400 );
// Seconds
if($seconds <= 60)
{
echo "$seconds seconds ago";
}
//Minutes
else if($minutes <=60)
{

   if($minutes==1)
  {
   echo "one minute ago";
   }
   else
   {
    echo "$minutes minutes ago";
   }

}
//Hours
else if($hours <=24)
{

   if($hours==1)
  {
   echo "one hour ago";
  }
  else
  {
   echo "$hours hours ago";
  }

}
//Days
else if($days <= 7)
{

  if($days==1)
  {
   echo "one day ago";
  }
  else
  {
   echo "$days days ago";
   }

}
//Weeks
else if($weeks <= 4)
{

   if($weeks==1)
  {
   echo "one week ago";
   }
  else
  {
   echo "$weeks weeks ago";
  }

}
//Months
else if($months <=12)
{

   if($months==1)
  {
   echo "one month ago";
   }
  else
  {
   echo "$months months ago";
   }

}
//Years
else
{

   if($years==1)
   {
    echo "one year ago";
   }
   else
  {
    echo "$years years ago";
   }

}

}
in the end I get the span tag with nothing in it and the text right before it. What am I doing wrong?