Host website on port 443?

I'm hosting a website on my Ubuntu Server. The website is up and running. I created an A record in GoDaddy.com to point the namespace to my public IP. All this is good but I'm only using port 80 (http). I want to use port 443, however if I use the namespace w/ port 443 I get my firewalls login page.

How can I use port 443 for both my website and for the firewall login page? I don't want to give up one for the other. I know it's something simple and stupid I just never hosted a website before, but I want to be secure with the connection.

Btw, this is all a home lap experiment.

Thanks