Suggest Treatment For Absence Of Menstrual Bleeding While On Rigevidon

Hi, I was on the Rigevidon pill for 3months, and took all of them regularly, as well as always used condom as a second extra protection. I stoped taking them in August as there was no further need, and didn t have sex after. After than I had regular period in September and October, however in November I didn t get my period and I m 17days late. Is that something related to just a lack of ovulation or should I be worried? As it might be cause by the stress of being scared that there s a chance of pregnancy? Many thanks