Some of you out there may be just like me: you just assumed (either by reading info online or using one of the many Ovulation Calculators) that you knew when you were ovulating. I went by the info I was getting online & figured I ovulated somewhere around day 14. Little did I know, I was a week off ! I bought a few packs of opk's and used them up through day 16 for two months, never getting a positive. I thought maybe I was reading them wrong or who knows, maybe I'm not ovulating. I joined fertilityfriend.com and starting charting my bbt; and this past cycle I decided to keep using the opk's past day 16 and got a positive on Day 19 and 20 and ovulated on Day 22. I'm now 3 dpo and so excited ! I just wanted to pass this information along, hoping it may help someone who might be in my shoes. :)