Can I Still Be Pregnant After Taking Modus Despite Negative Pregnancy Tests?

I had periods on 24th December.Before that I ve done protected Sex.And after 7 days of missing periods I consulted to a doctor cause in pregnancy kit no results was showing.Then did a urine pregnancy test from path lab.The result was also negative.Doctor told it maybe false negative report due to early test.I don t want to conceive now.So she prescribed me Modus 10. Is it possible to remain pregnant after taking Modus?