I haven't had my period in (almost) two months

I am an 18-year-old woman who had a unilateral oophorectomy in July of last year, where they also discovered that I had endometriosis. I was prescribed contraceptives for two months (August and September); I took them normally.

Then I had my period in October and November normally, without delays and without pain. It was normal until then. But, in December it didn't go down, and I have always been regular, so it seems very strange to me.

I'm 23 days late, and I'm anxious that I won't get anymore. Maybe I'm just being very paranoid? Even my aunts and mother had never had anything like this happen to them. I took the genetic lottery, and only I suffer from this in my close family. Has it happened to anyone else? :(