9 months without period!? Help.

I’m 20 yrs old and haven’t got my period. My last period was last week of November 2017, I visit my Ob gyn last september 2017 and she prescribe me to take a pills (Cybelle) i used it for 2 months ( I got my period for 2months) then i stop because i got worried. While taking pills my mood change i become moody and my hair is falling. After i stop taking a pills my period didn’t comeback. Today August(2018) I was planning to visit again my ob gyn but suddenly i feel pain in my lower abdomen and my period comeback 😵 I don’t know whats happening should i still visit my ob gyn? Anyone having the problem like me? please i need advice ( Sorry for my bad english)