You could remove the filter and add your search criteria to the xpath of your retrieve and then add the count action. This would result in a single database action (only the count) if the list is not used somewhere else. Your microflow would have a better performance.
Where do you have your filter criteria stored? Maybe we can help building the xpath if we know how your data is looking.
Let's say you have two variables $Date1 and $Date2 you can use those in the retrieve Xpath like:
[Day >= $Date1 and Day <= $Date2]
or if you want to use some tokens
[Day <= '[%BeginOfCurrentDay%] + 2 * [%WeekLength%]']
It is much better to use Xpath in your retrieve (as suggested by Ronald) than to filter the list. As the number of Orders increases the list filter operation will slow down and consume more memory. Whereas an Xpath retrieve will be more efficient.