Overflow Error in VBA code

Below is my code for the project I am doing, and for some reason I keep on getting an overflow error at the line:

totalAmountWeight = (ActiveWorkbook.Worksheets("Product Info").Cells(p, 8).Value) / (ActiveWorkbook.Worksheets("Product Info").Cells(p, 7).Value)

I am not sure why this error is occurring or how to fix it.

Private Sub Worksheet_Calculate()
Dim target As Range
Set target = Range("Q1")
Dim p As Long
Dim o As Long

Dim r As Long
Dim Length As Single
Dim Width As Single
Dim Height As Single
Dim totalAmountWeight As Double
Dim i As Integer, intValueToFind As Integer





Dim sheet As Worksheet

Set sheet = ThisWorkbook.Worksheets("Product Info")
'lastrow = sheet.Cells(sheet.Rows.Count, "B").End(xlUp).row
lastrow = Range("B" & Rows.Count).End(xlUp).Row

o = 1
r = 1

If Not Intersect(target, Range("Q1")) Is Nothing Then

For p = 2 To lastrow


Length = ActiveWorkbook.Worksheets("Product Info").Cells(p, 2).Value
Width = ActiveWorkbook.Worksheets("Product Info").Cells(p, 3).Value
Height = ActiveWorkbook.Worksheets("Product Info").Cells(p, 4).Value



totalAmountWeight = (ActiveWorkbook.Worksheets("Product Info").Cells(p, 8).Value) / (ActiveWorkbook.Worksheets("Product Info").Cells(p, 7).Value)

ActiveWorkbook.Worksheets("Backend").Range("O1").Value = totalAmountWeight

Call boxes(Length, Width, Height)
Call boxesLast3(Length, Width, Height)

intValueToFind = 0
For i = 2 To 7    ' Revise the 500 to include all of your values
    If ActiveWorkbook.Worksheets("Backend").Cells(i, 5).Value = intValueToFind Then
        'MsgBox ("Found value on row " & i)
        ActiveWorkbook.Worksheets("Backend").Cells(i, 7).Value = 600
        ActiveWorkbook.Worksheets("Backend").Cells(i, 8).Value = 400
        ActiveWorkbook.Worksheets("Backend").Cells(i, 9).Value = 325

        Else
            'MsgBox ("Value not found in the range!")
            'MsgBox ActiveWorkbook.Worksheets("Backend").Cells(i, 5).Value
    End If
Next i


Call LWextra(Height, Length, Width)
Call HWextra(Height, Length, Width)
Call LHextra(Height, Length, Width)
Call HLextra(Height, Length, Width)
Call WLextra(Height, Length, Width)
Call WHextra(Height, Length, Width)


newamount = ActiveWorkbook.Worksheets("Backend").Range("Q1").Value
dimensions = ActiveWorkbook.Worksheets("Backend").Range("K13").Value

ActiveWorkbook.Worksheets("Backend").Cells(o, 26).Value = newamount
o = o + 1

ActiveWorkbook.Worksheets("Backend").Cells(r, 27).Value = dimensions
r = r + 1

Next p

End If

End Sub