I'm 24 years old and I never got my periods from my childhood

I'm 24 years old and I never got my periods form my childhood I'm so worried about it.i consult a dr and he asked me to check the blood test and he  give me some medicine . after taking medicine periods came other time periods doesn't came It's really hard to get married. Without periods I can't get pregnant after marriage. So what I should do to get my periods.plg answer me