Late period but test negative?

So I'm using two different apps to watch my ovulation and my cycle normally lasts around 29 days on average. I got really sick on the depo and decided to forgo contraceptives for now. Since i got off the depo my period is amazingly regular! Haven't been late a month yet! During my ovulation week i want paying attention and was intimate work my husband 4 days before my ovulation. I am now 14 days late for my petiods and the last test i took was on wed, 8/26, at 12 days late and it was negative. :/ im not sure what's going on. Could i still be pregnant? Or is this just a fluke?