Help Please!

Ok so I'm needing some advice from you ladies. AF was due 2 days ago but nothing came so I tested yesterday with first morning urine and got a bfn. AF still isn't here and I'm always a regular 30 day cycle. I know I ovulated around the 6th since I use ovulation tests. AF last visited me on Feb 21st. Can someone help me to know why my pregnancy test was negative but my period is almost 3 days late? Anyone else have this happen to them? Thank you!