How Long Should Medication For PCOD Be Continued?

hi,i am 23 year old medical student.i have been diagnosed with pcod.i took pills for 3 months to regulate the cycles after which i had normal cycles for 6 months.my thyroid profile and FSH LH were normal. i dint have my last period and now doctor has suggested me metformin,nacfil,cycloset.foe how many months i have to take medicines?will i have ovulatory cycles?how can i check whether i am ovulating or nat? i am seriously worried,please help me out.