Function Return problem

Option Explicit

Private Function CleanStringToNick(strInput As String)
Do While Left(strInput, 1) = "!"
    DoEvents
    strInput = Right(strInput, Len(strInput) - 1)
Loop
strInput = Left(strInput, InStr(strInput, " "))
strInput = Left(strInput, Len(strInput) - 1)

CleanStringToNick = strInput
End Function

Private Sub Form_Load()
Dim strInput As String
strInput = "!nick abcdefghijklmnopqrstuvxyz"
MsgBox CleanStringToNick(strInput)
'strInput er nu "nick", hvorfor fanden har den ændret variablem i den her Sub ?!
Stop
End Sub