I am sure this has been asked before...but is it possible to ovulate and still get negative OPK results? I have both clear blue advance and some Amazon test strips. I do the advance with fmu like it says to and the strips in the morning and afternoon. all keep coming back negative. I am having some ovulation signs tho. Breast are fuller (not tender), my cp is high open and soft, and so far my cm is creamy. Today is day 13 for me. I feel like I should be at least getting the flashing smiley by now but so far it's nothing and I starting to run out of test and I hate to spend more money if it's not going to work.