Hi , I Have Got Married Since 2 Yrs Ago.

Hi , I have got married since 2 yrs ago. I have not conceived yet due to irregular cycle & pcod. Now I have started my pregnancy treatment , my doc advised me to regualrise my cycle so she gave 21 tabs of ovaral L for 2 months. 1st mnth I have got my periods on time and 2nd cycle I have not got my periods after 21 pills. Tuk pregnancy test it was nill. Again she gave me mensovit plus for 5 days though I dint get my cycle. What will be the cause. Cud any of u plz explain. ??