Just curious and need assurance

Problem/Goal:

I am concerned about the possibility of pregnancy. I am currently three days late for my expected period, and I want to know if my recent negative pregnancy test is reliable.

Context:

I had unprotected sex on January 22 and took the Yuzpe method as emergency contraception. Spotting started on January 23, followed by a heavy flow from January 24 to January 31. We have not had sex since then. I took a pregnancy test on March 1, which came back negative.

Previous Attempts:

I took the Yuzpe method immediately after unprotected sex, monitored my bleeding, and took a home pregnancy test.