Birth control and Plan B

So my last period was on January 16 and after that period I wasn’t on birth control and had unprotected sex where I took plan b a couple days later I started my birth control and I wasn’t on my period which I know to start your bc they say to take it on the first day of your period, but I’m on my sugar pills and still no period. Is there a chance I can be pregnant or maybe my system is all messed up?