BuddyPress.org

I am using the code below to create an activity feed post when a user submits a form. It works, but creates three activity posts instead of one. I think I have added the code in the wrong place, can anyone help?

$current_user = wp_get_current_user();
$user_login =  $current_user->user_login;
$username =  $current_user->user_firstname ;
global $bp;
$userlink= 'http://localhost/wordpress/member/'.$user_login;
$action = '@'.$username.' has just submitted a review on PAGENAME in CATEGORY';
global $bp;
bp_activity_add (
array(
'action' => $action,
'primary_link' => $userlink,
'component' => 'activity',
'type' => 'activity_update',
'user_id' => $bp->loggedin_user->id,
'item_id' => $bp->displayed_user->id
)
);

at the moment it is in the page that contains the form being used, is this not correct?