Hi I am Dr.D.Karthiga Sasi Kumar from Pondicherry
Welcome to Health Care Magic. I understand your concern.
I hope that you have crossed your expected date of the periods (currently 36 days) and did the testing which was found to be negative.If that so, and still not gained your periods please consult a gynaecologist and do an ultrasound
to know the real status.There are still chances if you had a delayed ovulation.
Hope this answer satisfies your query.
Feel free to consult me in future if necessary .