Login status doesnot change on successful login

hello guys.

while (rs.Read())
        {
            if (rs.GetString(0) == DropDownList1.SelectedValue)
            {
                pass = rs.GetString(1);
                secure = rs.GetString(2);
                if (pass == TextBox1.Text)
                {
                    FormsAuthentication.RedirectFromLoginPage(DropDownList1.SelectedValue, false);
                    Response.Redirect("~/users/FormIndex.aspx?username=" + secure);
                }
            }

            else
                Label3.Visible = true;
        }

this is my code behind file

whenever i enter my username and password it get successfully logined but my login status does not change to logout. it shows login after the successfull login