Lairdoz, I'm so sorry to hear that. Was this a stim cycle for you? Sorry, I can't remember. If it was, I find that the FSH injections make my LP very short. The progesterone counteracts that. Plus, when an EPU is done the corpus luteum which normally produces the progesterone is damaged or doesn't happen (can't remember which), so you need the progesterone introduced artificially to give the embies a chance.