Two days late.

Im 3 days late today. I had a positive ovulation test on the 4th and of course took advantage of it. I havent done a pregnancy test yet. Im tired of BFN lines. I have symptoms of fatigue, tiredness, gassy,nauseated and upset stomach but then again I sometimes get vertigo. If I ovulated on the 4th then I should've gotten my period by now if im not pregnant right? Doesnt your period start about 15 days after ovulation? My last period was on Nov 20th and my cycles are between 28 and 30 days long. According to Glow im 3 days late.