if you ovulated on the 5th, you would theoretically be only 7dpo. you can reach your positive typically anywhere from 10dpo on. some women can get a bfp earlier, but everyone is different. i would wait another 5-7days and retest. the key is to being relaxed about it. stressing can delay your period, giving you a false impression that you are pregnant.
the best thing to do is even to wait until af is late, that way your not playing games with yourself: "well, even though its negative, i might still be pg" or "well i'll just try again tomorrow" ... i know its hard, but to save a few extra bucks, wait until af is due to arrive to test again.
best of luck! we're pullin' for ya!