Prompt Error Messages if Row exceeded Limit

Hi, I have a macro file that allow me to combine all the files in the same workbook. My problem now is to prompt an error message if my combined sheet exceeded row limit. I'm not very good in VBA and i hope someone can amend the macro file for me.

Thank you very much

Apple

    Sub Combine()
    Dim J As Integer
    Dim R As Long
    
    On Error Resume Next
    Sheets(1).Select
    Worksheets.Add ' add a sheet in first place
    Sheets(1).Name = "Combined"

    ' copy headings
    Sheets(2).Activate
    Range("A1").EntireRow.Select
    Selection.Copy Destination:=Sheets(1).Range("A1")


    
    ' work through sheets
    For J = 2 To Sheets.Count ' from sheet 2 to last sheet
        Sheets(J).Activate ' make the sheet active
        Range("A1").Select
        Selection.CurrentRegion.Select ' select all cells in this sheets

        ' select all lines except title
        Selection.Offset(1, 0).Resize(Selection.Rows.Count - 1).Select

        ' copy cells selected in the new sheet on last line
        Selection.Copy Destination:=Sheets(1).Range("A65536").End(xlUp)(2)
      
    Next
End Sub