Negative ovulation tests

So I ordered the clear blue digital ovulation test off of amazon but so far I've gotten nothing but negatives, but me and my SO are having sex twice a day each day with pre seed. But so far I haven't gotten a smiley face and I'm almost running out of tests and I don't want to buy anymore neither does my SO. But my question is has anyone gotten pregnant but didn't get a positive on their ovulation tests?