Need help with code

[parteegolfer]

I have this code that detects the end of a workweek by date in column
(A)and when the Macro is run it inserts a row with "Weekly Subtotal" in
column (A). There are two issues I can't figuire out:

1) I need to sum up columns (D, E, and F) above each row till the next
"Weekly Subtotal" is detected or No date is detected (First entry in
column)

2) The way the code is now, if I run the Macro for a second time, a
duplicate row will be inserted below the last one that was inserted.
How can I keep this from happining.

Here is the code:

Sub weekdaycount()
Dim wrng As Range, lrng As Range
Dim count As Long

Set wrng = Cells(8, "a") '<<=== start range - change if need
Set lrng = Cells(Cells.Rows.count, "a").End(xlUp)
Do While (wrng.Row <= lrng.Row)
count = 1
Do While (Weekday(wrng) <= Weekday(wrng(2)))
If wrng(2) <> "" Then
Set wrng = wrng(2)
count = count + 1
Else
Exit Do
End If
Loop
Set wrng = wrng(2)
wrng.EntireRow.Insert
wrng(0) = "Weekly Subtotal"
Loop
End Sub