You can plot the same data in any other way and it will show you data for weeks.
But once I select the “Trends” visualization, it shows no data in previous weeks (comparing by days or months works in “Trends”, struggle is just with weeks):
Seems to be working ok here. What version of Metabase are you using?
Can you reproduce the issue using the Sample Database? I created a question on the Orders table, counting rows by week, then switched to the trend visualization and it correctly showed this week’s count and the previous week’s comparison.