Just need some guidance

I had sex with someone I have been seeing the past 7 mos and unexpectedly he finished inside me without me being aware, I took a plan b but realized that we hooked up the week of ovulation and I’m not sure if taking plan b would have an effect and my period was due this week and I am a few days late. I’ve taken 3 pregnancy tests and all have came back negative. Is it possible I’m just not pregnant and plan b delayed my period? Or is it possible that I am pregnant and tested too early?