Help! OPK question

[momof3trying4]

So we are TTC and this month I have started a whole list of different vitamins known to help with fertility since we have been TTC for 4 months and nothing I have been using OPK for the past 4 days. Today is my CD15 and I normally get a +OPK CD15 and CD16. I have had cramps on my lower right side which I assume are O cramps but still have not got a +OPK! Has anyone else had the cramping prior to a +OPK??? I hope we did not miss our chance this month