Can Period Get Delayed By A Month After Taking Norethisterone?

Hi, last month I took norethisterone to delay my period, however I did not take it at regular times. My period started fine after 3 days from when I stopped taking the medication. This month, my period is 7 days later than expected and I'm worried that I may be pregnant. MY boyfriend and I always use a condom as I am so worried about becoming pregnant. Is it normal for my period to be late one month after taking norethisterone?