Is this using a Monday to Saturday calendar or a Sunday to Saturday calendar?
The date ranges in the Query Builder use the Geogorian callendar by default. You can customize your date range to start on any day by using the custom callender or I advise just editing a Fiscal callender. To do so, change the drop down to Fiscal and click the edit icon (pencil). Then give it a new name and change the start of week date.