For those of you who haven't experienced this before, don't worry about it.

Occasionally the site will croak like this, often when the site gets a ton of traffic.

Normally it coincides with a popular anime release, but with it being Thanksgiving in America, I'm sure there's a burst of people with free time.

Anyways, just be patient until the team can get things up and running again.
Your watchlist will be fine so no worries, though it's a good time to remind you to export your watchlist regularly!