My project Wow Log Parser disappeared just as the new site went live. I cannot find it in the "My curse" tab and I cannot find it anywhere else either.

Our author site CurseForge is where you should be managing your projects.  Curse will automatically sync projects from CurseForge at regular intervals.

CurseForge has many author-friendly features that far eclipse what was available to you on curse.com

So all projects that were not on curse forge before the move to the new site are deleted?

Well, I remade the project on curseforge since nobody seems especially eager to fix the problem.