Third month using it now, first month had high then ovulation on day 12, second month highs then ovulation on day 15, it's now day 18 and I've been having highs since day 11 - is there a chance I'm not going to ovulate this month? I think I read that once you get a high you keep getting highs until ovulation but it seems to far along now to ovulate - any pros out there with advice?