Launching a website is perhaps the smallest milestone there is, it's no more momentous to me than starting a new work week. It's a chance to take a breath and open up a new channel to your (hopefully) new users. You're not ending your work load, you're pretty much doubling it.
At least that's how I always thought of it. I love make sites for people to use, and I love to listen to what they have to say and respond as fast as I can to make the site better. It's perhaps my favorite thing to do, and it saddens me when I can't respond fast enough.
Like launching a boat or a rocket, you're not standing by watching the boat sail off into the sunset or watching the rocket climb into outer space--you're on it.