Confused on DPO

Meghan • Fri, Feb 06

Hi, I'm new to all of this. Can someone explain to me how many DPO I am, Since today is the 5th of February? I attached a pic of last month for me, I'm 3 days late on my period. I was suppose to start on the 2nd of February, and I took a test yesterday morning and got a BFN. Is it still possible to be get a BFP? Thanks!