Using String Manipulation To Create And Change Wroksheet Name.

i have a worksheet called 'week 1' and want to write vba code so that a new sheet called 'week 2' can be created. However i want to write code so that it doesn't matter what sheet i am on, a new sheet would be created with the name week and the next number up. ie. the last worksheet is 'week 7' then the code should be able to create a new worksheet called 'week 8' ect. I currently have this code but it keeps returning an error message. anyone know how i could do this???

Sub nSheet()
Dim nm, i As Long
nm = Worksheets(Worksheets.Count).name
i = 1
Sheets.Add
Do While WorksheetExists(Left(nm, Len(nm) - 1) & i)
i = i + 1
Loop
ActiveSheet.name = Left(nm, Len(nm) - 1) & i
End Sub