I may be incorrect in what appears when you visit your domain. It could be that it's in "Parked" mode, rather than Fully Hosted.
Go back to the DreamHost panel for Manage Domains and click Edit in the Web Hosting column for your domain.
That will bring up a page with all the hosting options for your domain. At the top of the screen is the Fully Hosted domain section. If it's in Fully Hosted mode, you'll see a green (Active) tag there. It's possible you're in Parked mode, in which case farther down you'll see Parked (Active).
At the bottom of the Fully Hosted box, you'll see a "Change Settings" button. Click that one. That should clear up the issue once the change propagates to your server, which might take a few minutes.