You can calculate the dates for the previous week like so
Code:
WHERE [some_date_field] >= Date()-Weekday(Date(),2)-6 AND [some_date_field] < Date()-Weekday(Date(),2)+1
Date()-Weekday(Date(),2)-6 = the monday of the previous week
Date()-Weekday(Date(),2)+1 = the monday of the current week
So the code above is filtering down to the dates greater than or equal to 12:00AM last monday and before 12:00AM the current monday.
*Side note that date fields are date+time fields, so just remember to that into account when working with date fields. It might display March 22, 2020 but it could actually equal #March 22, 2020 11:17:31 AM#.