i haven't gotten my period in a while

I'm 2 weeks late, however I started Birth control 2 weeks ago as instructed by my doctor, the day I started it my period was already 3 days late. Which isn't rare for me but am I supposed to get my period on Birth control? And if I take a pregnancy test will it be effed up bc of the birth control.
If i am pregnant(big if!) would my kid be definetly fucked up by now?  I have to finish this week before I get to the sugar pill.