Someone Help !!

Markisha

My last period was February 10th, and I’m confused. I’m not sure if I should add on 2-3 days for my cycle because it was a short month or what. I’m 16 dpo, and supposedly as of 12 tonight 3 days late. Tests keep showing negative, but I don’t know if it’s because of it being to early and I need to wait a week or is it because my period is coming. What do you guys think?