Quick question ?

This month after I receive a positive ovulation test me & my partner BD  the morning before the positive test & the next day afternoon. I'm expecting my AF in 4 days but I'm currently not having any symptoms of me starting my AF. I always have PMS every month. Acne , Breast usually sore, cramps, mood swings , cravings for sweets & etc . I took a pregnancy test & it was a BFN but do you think it's Negative because it's too early to detect rather I'm pregnant now ?