My wife had a blinking smiley on day 14 of her cycle, a solid smiley on day 15, and we tested day 16 just to see and it read low fertility. I was under the impression that solid smiley meant you were at your peak for 24-48 hours and there were less than 12 between her blink and her solid, and her solid to the low fertility open circle. Does this mean her luteal phase is short and could we have difficulty conceiving?