PHP Post Automatically Firing On Page Load?

Question

I am making a simple PHP login with POST. However, every time I load the page, the function gets fired before I even hit submit on the html form. I have tried the method below and isset($_POST['submit']) but both ways are firing every single time I load the page. How do I stop this from occuring? Thank you.

//PHP CODE ABOVE HTML

    <?php
    
    $serverName = "localhost";
    $dBUserame = "blake";
    $dBPassword = "password";
    $dBName = "database";
    
    session_start();
    
    $conn = mysqli_connect($serverName, $dBUserame, $dBPassword, $dBName);
    
    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }
    
    
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
    
        $email = mysqli_real_escape_string($conn, $_POST['email']);
        $password = mysqli_real_escape_string($conn ,$_POST['password']);
    
            $sql = "SELECT * FROM users WHERE email = '$email' AND password = '$password'";
    
            $result = $conn->query($sql);
    
            if ($result->num_rows > 0) {
    
                $_SESSION['useremail'] = $email;
    
                header('Location: https://allevohealth.com/admin/newsletter/contacts.php');        
    
                // output data of each row
    
                while ($row = $result->fetch_assoc()) {
    
                   $_SESSION['name'] = $row["fullname"];
    
                   $_SESSION['email'] = $row["email"];
    
                   $_SESSION['useridid'] = $row["id"];
    
                   echo "<br> Full Name: ". $row["fullname"]. " - Email: ". $row["email"]. " " . $row["passsword"] . "<br>";
    
                }
            } else {
    
                echo "0 results";
            }
    
            $conn->close();
    }
    
    ?>


//HTML CODE BELOW PHP

                <div class="col-lg-12 row justify-content-center">
                    <div class="col-lg-4 col-md-8 col-sm-9 mb-5">
                        <div class="p-5" style="border-radius: 20px !important; background-color: #161621">
                            <form id="myform" method="post">
                                <h2 class="h4 text-white mb-5">ACCOUNT LOGIN</h2>
                                <div class="row form-group">
                                    <div class="col-md-9">
                                        <label class="text-white" for="email">EMAIL</label>
                                        <input type="email" id="input-email" name="email" class="form-control rounded-0">
                                        <p id="result" style="padding-top: 2%; font-weight: bold;"></p>
                                    </div>
                                </div>
                                <div class="row form-group">
                                    <div class="col-md-7 mb-3 mb-md-0">
                                        <label class="text-white" for="password">PASSWORD</label>
                                        <input type="password" name="password" id="input-password" class="form-control rounded-0">
                                    </div>
                                </div>
                                <div class="row form-group">
                                    <div class="col-md-12" style="padding-top: 5%">
                                    </div>
                                </div>
                                <input type="submit" name="submit" value="LOGIN" style="width: 150px" class="btn btn-primary mr-4 mb-2">
                            </form>
                        </div>
                    </div>
                </div>