If you think your ovulation day was 3/12/18, then you should have had periods by now as second part of menstrual cycle is usually fixed one of 14 days. It means, once ovulation has occurred , if not fertilised then there will be periods by 14 days since ovulation.
Usually, the chance of pregnancy in the postovulatory safe days are very low.
So, my advice would be to do urine
pregnancy test, if negative wait for 1 more week and test it again if you still don’t get your periods, provided you are fine without any pain or any other symptoms. If you are very anxious you have the option of testing pregnancy hormone in blood but I don’t advise that unless there is a valid reason.
Irrespective of the result please, contact a gynaecologist near by to get reviewed completely.
The purpose is, a detailed history and relevant examination is important because - your regular menstrual cycle length in past 12 cycles should be considered before calculating your safe and unsafe days
If 26 to 32 days cycle then unsafe days are between 8-19 .
Withdrawal methods are less effective
Change in environment, stress etc can affect menstrual cycles as well.