If you used to duplicate from the three-dot menu in the old portal, this moved in the new portal.
You can still duplicate a drop (including +1 week) without rebuilding everything from scratch.
Quick answer
In the new portal, duplication starts from the Create a drop button in the top right of your Drops page.
How to duplicate a drop
Go to Drops.
Click Create a drop (top right).
Choose or type in the drop you want to copy.
Duplicate as is or Duplicate +1 week to copy the drop forward 1 week
Open the new draft and review.
Publish when ready.
You can also duplicate a Completed drop by clicking into it and hitting Duplicate at the bottom.
Before you publish your duplicate
Be sure to update
Your drop title
Drop text