Talk to Gynecologist on Gynecology

I am taking this medicine (Pregnacare Conception) from last three weeks, right after my periods. last month i got my periods on 14th of august and in the previous month I got my periods on 17th of July, 20th of June and the previous one were on 17th of May. This month I have severe periods pain from 8th of September but still I have not gotten my periods. can you please guide me what is the reason of this pain and there are still any chances of pregnancy or not and when should I go for Pregnancy test?