PHP Coding for a Registration page.

I have a registration page where the data is not going into the database and I am receiving two errors. 

Following is my code:

$q = "SELECT id FROM users WHERE email=?";
        $stmt = mysqli_prepare($db, $q) or trigger_error("Query: $q\n<br>MySQL Error: " . mysqli_error($db));
        mysqli_stmt_bind_param($stmt, "s", $e);
        mysqli_stmt_execute($stmt) or trigger_error("Query: $q\n<br>MySQL PS Error: " . mysqli_stmt_error($stmt));
        $r = mysqli_stmt_get_result($stmt);
    if (mysqli_num_rows($r) == 0) { 
            
        
// Create the activation code:
        $a = md5(uniqid(rand(), true));
            
// Add the user to the database: 
   // Make the query:
  $q = "INSERT INTO users (tomorrowdate, first_name, mid_initial, last_name, username, email, pass, active, agree, date_expires) VALUES (?, ?, ?, ?, ?, ?, ?, '$a', 'Agree', DATE_ADD(NOW(), INTERVAL 2 YEAR) )";
            
    // Prepare the statement:
$stmt = mysqli_prepare($db, $q);
            
// Bind the variables:
mysqli_stmt_bind_param($stmt, 'ssssssss', $tomorrowdate, $first_name, $mid_initial, $last_name, $username, $email, $pass, $a);

// Assign the values to variables:

$tomorrowdate = $_POST['tomorrowdate'];
$first_name = $_POST['first_name'];
$mid_initial = $_POST['mid_initial'];
$last_name = $_POST['last_name'];
$username = $_POST['username'];
$email = $_POST['email'];
$pass = $_POST['pass'];
$a = md5(uniqid(rand(), true));
    
    
// Execute the query:
 mysqli_stmt_execute($stmt); 

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Following are the two error messages; 

An error occurred in script '/XXX.com/Register.php' on line 103: Undefined index: pass
Date/Time: 6-18-2023 20:35:10 - Line 103 - $pass = $_POST['pass'];

An error occurred in script 'xxxxxxxf.com/Register.php' on line 93: mysqli_stmt_bind_param(): Number of variables doesn't match number of parameters in prepared statement
Date/Time: 6-18-2023 20:35:10 - Line 93 - mysqli_stmt_bind_param($stmt, 'ssssssss', $tomorrowdate, $first_name, $mid_initial, $last_name, $username, $email, $pass, $a);