Help!No period after 1 week of taking Plan B!And period is delayed overall!!?

I also had to take the plan b pill after my husband and I miscalculated my fertile days. The doctor told me that the pill would most likely interfere with when my period would start-being anywhere from one week later to three weeks after I take the pill. My period ended up starting on time. If you haven't started by the third week after taking the pill, just to be safe take a home pregnancy test or go back to the doctor where you got the pill for them to give you a test there. If there was no , then stress or a change in your lifestyle is prob what's been throwing your periods off. It happens to all of us. Good luck.