Help me finalize a contact form on theme I am building

Ok, first of all, this is going to be a huge amount of code. Sorry for that. I am not finding a way to make this contact form on my theme work.
Here is the form itself:

<!-- Contact Section -->
<section id="contact">
    <div class="container">
        <div class="row">
            <div class="col-lg-12 text-center">
                <h2><?php echo get_theme_mod('contact_title', 'Contact Us'); ?></h2>
                <hr class="star-primary">
            </div>
        </div>
        <div class="row">
            <div class="col-lg-8 col-lg-offset-2">
                <form name="sentMessage" id="contactForm" novalidate>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label><?php _e( 'Name', 'bootfreela' ); ?></label>
                            <input type="text" class="form-control" placeholder="Name" id="name" required data-validation-required-message="<?php _e( "Please, enter your name.", "bootfreela" ); ?>">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label><?php _e( 'Email Adress', 'bootfreela' ); ?></label>
                            <input type="email" class="form-control" placeholder="Email Address" id="email" required data-validation-required-message="<?php _e( "Please enter your email address.", "bootfreela" ); ?>">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label><?php _e( 'Subject', 'bootfreela' ); ?></label>
                            <input type="text" class="form-control" placeholder="Subject" id="subject" required data-validation-required-message="<?php _e( "Please enter your subject.", "bootfreela" ); ?>">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label><?php _e( 'Message', 'bootfreela' ); ?></label>
                            <textarea rows="5" class="form-control" placeholder="Message" id="message" required data-validation-required-message="<?php _e( "Please enter a message.", "bootfreela" ); ?>"></textarea>
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>

                    <div id="success"></div>
                    <div class="row">
                        <div class="form-group col-xs-12">
                            <button type="submit" class="btn btn-success btn-lg"><?php _e( 'Send', 'bootfreela' ); ?></button>
                        </div>
                    </div>
                </form>
            </div>
        </div>
    </div>
</section>

Now, the Js file that handles it (jqBootstrapValidation):

(function($) {

$("input,textarea").jqBootstrapValidation({
    preventSubmit: true,
    submitError: function($form, event, errors) {
        // additional error messages or events
    },
    submitSuccess: function($form, event) {
        event.preventDefault(); // prevent default submit behaviour
        // get theme path
        var stylesheet_directory_uri = ContactMe_uri.templateUrl;
        // get values from FORM
        var name = $("input#name").val();
        var email = $("input#email").val();
        var subject = $("input#subject").val();
        var message = $("textarea#message").val();
        var firstName = name; // For Success/Failure Message
        // Check for white space in name for Success/Fail message
        if (firstName.indexOf(' ') >= 0) {
            firstName = name.split(' ').slice(0, -1).join(' ');
        }
        $.ajax({
            url: stylesheet_directory_uri+"/inc/contact-me.php",
            type: "POST",
            data: {
                name: name,
                subject: subject,
                email: email,
                message: message
            },
            cache: false,
            success: function() {
                // Success message
                $('#success').html("<div class='alert alert-success'>");
                $('#success > .alert-success').html("<button type='button' class='close' data-dismiss='alert' aria-hidden='true'>×")
                    .append("</button>");
                $('#success > .alert-success')
                    .append("<strong>Your message has been sent. </strong>");
                $('#success > .alert-success')
                    .append('</div>');

                //clear all fields
                $('#contactForm').trigger("reset");
            },
            error: function() {
                // Fail message
                $('#success').html("<div class='alert alert-danger'>");
                $('#success > .alert-danger').html("<button type='button' class='close' data-dismiss='alert' aria-hidden='true'>×")
                    .append("</button>");
                $('#success > .alert-danger').append("<strong>Sorry " + firstName + ", it seems that mail server is not responding. Please try again later!");
                $('#success > .alert-danger').append('</div>');
                //clear all fields
                $('#contactForm').trigger("reset");
            },
        })
    },
    filter: function() {
        return $(this).is(":visible");
    },
});

$("a[data-toggle=\"tab\"]").click(function(e) {
    e.preventDefault();
    $(this).tab("show");
});
}(jQuery));
/*When clicking on Full hide fail/success boxes */
jQuery('#name').focus(function() {
jQuery('#success').html('');
});

On my functions.php file, I have this piece of code, to get theme path for JavaScript file.

function get_theme_directory_uri() {
  $stylesheet_directory_uri = array( 'templateUrl' => get_stylesheet_directory_uri() );
  wp_localize_script( 'contactMe', 'ContactMe_uri', $stylesheet_directory_uri );
}
add_action( 'wp_enqueue_scripts', 'get_theme_directory_uri' );

Then I have this contact-me.php file:

if( empty($_POST['name'] )      ||
empty( $_POST['email'] )    ||
empty( $_POST['subject'] )  ||
empty( $_POST['message'] )  ||
!filter_var( $_POST['email'], FILTER_VALIDATE_EMAIL ) ) {
    echo "No arguments Provided!";
    return false;
}

$name = $_POST['name'];
$email_address = $_POST['email'];
$subject = $_POST['subject'];
$message = $_POST['message'];

// Create the email and send the message
$to = "mauroluis@terra.com.br";
$email_subject = "Website Contact Form: $subject";
$email_body = "You have received a new message.\n\n"."Here are the details:\n\nName:       $name\n\nEmail: $email_address\n\nSubject: $subject\n\nMessage:\n\n$message";
$headers .= "Reply-To: $email_address";

wp_mail( $to, $email_subject, $email_body, $headers );

return true;

But it is not working. Someone said that the problem is that WP is not loading.

So I tried inserting this on my contact-me.php file, as suggested:

define( 'WP_USE_THEMES', false );
 require_once( $_SERVER['DOCUMENT_ROOT'] . '/wp-load.php' );

But still no good results.

Any help?