Hi On Saturday And Sunday I Took My Sugar Pill

Hi on Saturday and Sunday I took my sugar pill instead of my birthday control by accident and on Saturday I had sex.my boyfriend did not ejaculate and on Monday after I figured out what happened I took plan B. My pharmacy mentioned I should start a new pack of my birthcontrol and so I did because I was about 3 weeks into my 28 pill day cycle. I would have been on my period in 5 day from Saturday. Should I do anything to prevent pregnancy? Is there a large chance that I could be pregnant? How long do I have to wait to take a pregnancy test? Thanks