My host just upgraded servers a couple weeks ago, and MT was working fine on the new server until this weekend. Suddenly, I couldn't access the editing page and I got an Invalid ID error when viewing comments.

I changed the password in the mt-db-pass.cgi file to the new password from the upgrade and updated the config file to the new server name, which got me access to the edit page, but the comments were still not working. I also had to change a few permissions.

I noticed in the edit page that a few of my preferences weren't as I had selected, so I corrected them and saved. When I clicked "rebuild site," my whole site reverted back to when I originally installed the software in June with some of my CSS changes. (I checked through FTP and noticed that all of the dates are old, even though I made many changes before the site went live a couple weeks ago, after the server upgrade.)

Is this a problem with MT and not with my new server since it was working up until a few days ago? Can I do anything besides build all of the templates again and reimport my entries? Is there any way I can go back to how it was, or is it all over now that it's reverted?

were there any changes to your database?

My database is hosed. All that's there are the reverted entries. I'm pouring another glass of wine and working on recreating the site.