Filter Function not filtering weeks

Hi guys

Below is  a simple dax code i've written. Everything is working well except after adding the last filter function of "<Weekno" . The visuals results a blank value. However, if i do hard code a "2" instead of the "<Weekno", the function seems to be working fine.
Is there something wrong with my variable?

VAR Weekno = SELECTEDVALUE(Calendar_Lookup[Week No]) 

RETURN

CALCULATE(COUNTROWS(AP_Automation),FILTER(AP_Automation,AP_Automation[Contact Email]=RELATED('Account List'[Contact Email]) && AP_Automation[Category] = "Won"),FILTER(ALL(Calendar_Lookup),Calendar_Lookup[Week No]<Weekno))

 
Thanks for your help