Since you had sex around the time of your ovulation, there's a good chance that you could have gotten pregnant, especially if you were trying to conceive. If you were using a reliable form of birth control, of course, your chances are much lower.
Since your period was not due for over a week when you took the pregnancy test, the results aren't reliable. It can be tempting and exciting to start testing as soon as you feel pregnancy symptoms, but it's not really a good idea because no home pregnancy test can give you a correct result that early.
Even though you may have conceived by definition of the egg being fertilized during ovulation, the fertilized egg must adhere to the wall of your uterus before your body starts sending out the pregnancy hormones that at-home tests detect. This is called implantation and doesn't happen until seven to ten days AFTER the egg is fertilized and after implantation occurs, it still takes another two days before your body starts sending out those hormones.
You don't want to start taking pregnancy tests until around five days before your period is due, at the earliest.
For the most accurate results, you should wait to take a pregnancy test until the day your period is due.