Apache2 https keeps redirecting (301) to http

Even though I've used Apache for years, I'm new to https and SSL with Apache. For testing, I have executed some openssl commands as found on the Internet to generate a self-signed cert for use with Apache. When I hit an https://mydomain URL for the first time, I got the browser warning about the cert, which was expected. After accepting the cert in my browser(s), it seems that all https URLs are redirecting to the http equivalents with a 301.

I can't determine why. Any clues? I have one .htaccess file in the root of the public dir, but I don't think it is the cause (there is no mention of https).

This is Gentoo Linux, Apache 2.2.11.

Here is a portion of my Apache config. Most of it is just what came with Gentoo's Apache installation by default.

<IfDefine SSL>
<IfDefine SSL_DEFAULT_VHOST>
<IfModule ssl_module>
    Listen 443
    NameVirtualHost *:443

    <VirtualHost *:443>
        ServerName mydomain.com
        Include /etc/apache2/vhosts.d/default_vhost.include
        ErrorLog /var/log/apache2/mydomain.com.ssl.errors
        CustomLog /var/log/apache2/mydomain.com.ssl.log combined

        <IfModule log_config_module>
        TransferLog /var/log/apache2/ssl_access_log
        </IfModule>

        SSLEngine on

        SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP:+eNULL

        SSLCertificateFile /etc/apache2/ssl/mydomain.com.crt
        SSLCertificateKeyFile /etc/apache2/ssl/mydomain.com.key
        SSLOptions StrictRequire

        <FilesMatch "\.(cgi|shtml|phtml|php)$">
        SSLOptions +StdEnvVars
        </FilesMatch>

        <Directory "/var/www/localhost/cgi-bin">
        SSLOptions +StdEnvVars
        </Directory>

        SSLProtocol all -SSLv2

        <IfModule setenvif_module>
        BrowserMatch ".*MSIE.*" \
            nokeepalive ssl-unclean-shutdown \
            downgrade-1.0 force-response-1.0
        </IfModule>

        <IfModule log_config_module>
        CustomLog /var/log/apache2/ssl_request_log \
            "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
        </IfModule>

        RewriteEngine On

        DocumentRoot "/var/www/mydomain.com/public"
        <Directory "/var/www/mydomain.com/public">
            SSLRequireSSL
            Options Indexes FollowSymLinks ExecCGI
            AllowOverride All
            Order allow,deny
            Allow from all
        </Directory>

    </VirtualHost>

</IfModule>
</IfDefine>
</IfDefine>