Delayed Periods. Prescribed Cycloset Syrup. Negative Pregnancy Test. Safe To Take Medication?

periods missed for about 1 week, we have done pregnancy test . It reflects as negative.We have consulted a doctor. Doctor said as all fine & given cycloset syrup. But we have checked in internet that says as You can wait for another week & do Pregnancy test, It may have a chance to turns as positive. My doubt is weather i can take this cycloset syrup from now onwards or after 1 week. After 1 week it may turns positive - chance there or not.