Opk ??

Hi all, my husband and I have been ttc for 9 months, this is the first month I've used opks. I tested twice yesterday and both times I got a faint line, not quite as dark as the control line but pretty close. I tested again this morning and expected it to be positive, but NOTHING showed up.. not even a faint line.. anyone have any ideas what this means? Did I not ovulate?? :-(