I've just had my bloods taken today (im in CD 3) but he said it won't make much difference. Then he said do day 21 but that's Christmas day and the doctors are closed. So I don't know whether to do it in the 24th and or the 28th. My cycles have been 36, 32, 29, 33, 32 for the last 6 month. Would it be best to do it earlier or later?