you can use this
$user = new wp_user(get_current_user_id());
function commentCount() {
global $user;
global $wpdb;
$count = $wpdb->get_var('SELECT COUNT(comment_ID) FROM ' . $wpdb->comments. ' WHERE comment_author_email = "' . $user->data->user_email . '" and comment_approved = 1');
return $count;
}
echo ”;
echo commentCount();