How to combine hidden sheets using VBA

[help]

I have a worksheet and I'm trying merge multiple hidden sheets together I only want the hidden sheets the visible sheets I don't want to merge them. Currently I'm using this code:

Sub Combine()
'UpdatebyExtendoffice20180205
    Dim I As Long
    Dim xRg As Range

    On Error Resume Next
    Worksheets.Add Sheets(1)
    ActiveSheet.Name = "Combined"

   For I = 2 To Sheets.Count
            Set xRg = Sheets(1).UsedRange
            If I > 2 Then
                   Set xRg = Sheets(1).Cells(xRg.Rows.Count + 1, 1)
            End If

            Sheets(I).Activate
            ActiveSheet.UsedRange.Copy xRg
    Next
End Sub

I'm new to using VBA therefore I would like to ask if someone can help combine only the hidden sheet