'Problems determining the 1st Sunday in a month

This following if segment is not working right. What I want to do is do something special if and only if it is the 1st Sunday of the month and something else every other day. It appears to work for everything except if it is Sunday and day is <= 7 (1st Sunday of the month). Any help is appreciated.

    @echo on
    rem use for testing only
    set mydow="Sunday"
    set myday=5
    if not "%mydow%"=="Sunday" goto NotRightDay
    if %myday%<=7 goto FirstSunRoutine
    goto over

    :FirstSunRoutine
    echo This is the 1st Sunday routine
    goto over

    :NotRightDay
    echo This is not the 1st Sunday of the month
    goto over

   :over
   echo done


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