my period is late

Josselyn
My period is late 3 days counting today. My last period was march 11 midnight. Idk if i should count it as march 12?? I didn't really have unprotected sex. Atleast once or twice but he didn't cum in me. I took a pregnancy test it came out negative. I feel cramps and other symptoms i get usually before my period but it doesn't come!!! IM STRESSED OUT