Plan b question

So I was on day 5 of my period and I had sex with my bf.We used condoms and pull out.I was riding him and when he told me that he will cum I got up and when I turned the lights on I had sperm on my tights and we saw that the condom broke.I took plan B like 20 min after but I am kinda worried.On the next day I had no period for the whole day and then suddenly in the evening I felt blood.I saw it, it was brown.Is this from the pill and does it mean that it worked?Because in the website of the brand of the pill is said that your period should come in 5 days after you take the pill.