What Is The Function Of M2 Tone Syrup?

Hello Doctor.I was on birth control pills for a year and i stopped it 5 months ago. My periods didn t return since the time i stopped them. One of my doctor suggested M2 tone syrup for my periods to return. I took one spoon of M2 tone and my periods returned very next day.However I skipped it on the second day of my periods and my periods stopped on the third day. Did this happen because i skipped the syrup intake? Does this syrup also have the same effect as birth control pills which regulates the periods through artifical harmones? Can I get pregnant while using M2 tone?Is it safe to take this syrup?