No period but negative test?

My period is late by 5 days. I took a test yesterday at noon, and it came back negative. I have only had sex once in May, (protected) and still took a plan B. Then once again about three weeks ago (also protected). We occasionally “grind” and he once put the tip inside me for like 1 second. Literally went in and out dry as can be. Why is my period late? *side note- my period came twice in May and a week early in June. Are these side affects from the plan b? The past few days I’ve had tender boobs and thought I felt cramps coming... but nothing seems to be here. I have never been this scared and have no one in my life to talk to about this. Someone please help me