Formula to Generate Which week of the year it is based on date entered in ""Process Date"" Field.

Here is a simplified version using your process date

Create a formula date field called 
 Ending Saturday of First Week of Year 

LastDayOfWeek(FirstDayOfYear(Today()))


Create a field for Week number

var text 
var number WeeksSinceFirstWeek = 
(ToDays(LastDayOfWeek([Process date])-[Ending Saturday of First Week of Year]))/7;

$WeeksSinceFirstWeek+1