Login page just loads the php script when logging in

Question

Working on a website implementing login features for coursework. Currently have script files written but when i test it , it loads login.php which is what im using for the script.

<form action="login.php" method="post"> 
        <div class="imgcontainer">
            <img src="img/icons/avatar.png" alt="ELEAGUE" class="avatar">
    </div>

    <div class="container">
        <label><b>Username</b></label>
        <input type="text" name="username" maxlength="40"> 


        <label><b>Password</b></label>
        <input type="password" name="pass" maxlength="50">

        <button type="submit">Login</button>
        <input type="checkbox" checked="checked"> Remember me
    </div>

    <div class="container" style="background-color:#fff">
        <span class="psw">Forgot <a href="#">password?</a></span>
    </div>
</form>

And the script is

<?php 
//Connects to your Database 
$conect = mysqli_connect("db location","username","password", "forks") or die(mysql_error()); 
//Checks if there is a login cookie
if(isset($_COOKIE['ID_your_site'])){ //if there is, it logs you in and directs you to the members page
    $username = $_COOKIE['ID_your_site']; 
    $pass = $_COOKIE['Key_your_site'];
    $check = mysqli_query($conect, "SELECT * FROM users WHERE username = '$username'")or die(mysql_error());
    while($info = mysqli_fetch_array( $check )){
        if ($pass != $info['password']){}
        else{
            header("Location: login.php");
        }
    }
 }
 //if the login form is submitted 
 if (isset($_POST['submit'])) {
    // makes sure they filled it in
    if(!$_POST['username']){
        die('You did not fill in a username.');
    }
    if(!$_POST['pass']){
        die('You did not fill in a password.');
    }
    // checks it against the database
    if (!get_magic_quotes_gpc()){
        $_POST['email'] = addslashes($_POST['email']);
    }
    $check = mysqli_query($conect, "SELECT * FROM users WHERE username = '".$_POST['username']."'")or die(mysql_error());
 //Gives error if user dosen't exist
 $check2 = mysqli_num_rows($check);
 if ($check2 == 0){
    die('That user does not exist in our database.<br /><br />If you think this is wrong <a href="login.php">try again</a>.');
}
while($info = mysqli_fetch_array( $check )){
    $_POST['pass'] = stripslashes($_POST['pass']);
    $info['password'] = stripslashes($info['password']);
    $_POST['pass'] = md5($_POST['pass']);
    //gives error if the password is wrong
    if ($_POST['pass'] != $info['password']){
        die('Incorrect password, please <a href="login.php">try again</a>.');
    }

    else{ // if login is ok then we add a cookie 
        $_POST['username'] = stripslashes($_POST['username']); 
        $hour = time() + 3600; 
        setcookie(ID_your_site, $_POST['username'], $hour); 
        setcookie(Key_your_site, $_POST['pass'], $hour);     

        //then redirect them to the members area 
        header("Location: members.php"); 
    }
}
}
else{
// if they are not logged in 
?>

any help is appreciated, thanks