Plan B

I took a plan B 25 days ago, 3 days after my period. I took another plan B yesterday morning. (I normally never take these, I’m usually always careful). My period is now 4 days late, I’ve taken multiple pregnancy test & they are all negative. Is this normal after taking plan B?? I always have my period on time every month, so I’m kinda freaking out but all the test are negative. I did experience brown spotting after taking the first pill & that was it.