PHP登录出现Too Many Redirect Loop错误

请帮帮我。我每次登录都会出现这个错误。-"此网页有一个重定向循环ERR_TOO_MANY_DIRECTS"请帮帮我，我会非常感谢你的帮助。谢谢

这是我的index.php

<?php
include('login.php'); // Includes Login Script
?>

这是我的login.php

<?php
session_start();
$error = "";
if (isset($_POST['submit'])) {
    if (empty($_POST['email']) || empty($_POST['password'])) {
        $error = "Username or Password is invalid";
    } else {
        // Define $username and $password
        $usernameLogin = $_POST['email'];
        $passwordLogin = $_POST['password'];
        // Establishing Connection with Server by passing server_name, user_id and password as a parameter
        $connection = mysql_connect("localhost", "apple", "Apple318992");
        // To protect MySQL injection for Security purpose
        $username = stripslashes($usernameLogin);
        $password = stripslashes($passwordLogin);
        $username = mysql_real_escape_string($username);
        $password = mysql_real_escape_string($password);
        // Selecting Database
        $db = mysql_select_db("TS", $connection);
        // SQL query to fetch information of registerd users and finds user match.
        $query = mysql_query("select * from Users where password='$password' AND email='$usernameLogin'", $connection);
        $rows = mysql_num_rows($query);
        if ($rows == 1) {
            $_SESSION['login_user'] = $usernameLogin; // Initializing Session
        } else {
            $error = "Username or Password is invalid";
        }
    }
}

if (isset($_SESSION["login_user"])) {
    header("Location:timesheets.php");
}
?>

这是我的会话.php

<?php
include ('DBConnect.php');
session_start(); // Starting Session
// Storing Session
$user_check = $_SESSION['login_user'];
// SQL Query To Fetch Complete Information Of User
$ses_sql = mysql_query("select email from Users where email='$user_check'", $conn);
$row = mysql_fetch_assoc($ses_sql);
$login_session = $row['email'];
if (!isset($login_session)) {
    mysql_close($conn); // Closing Connection
    header('Location: index.php'); // Redirecting To Home Page
}
?>