I had a cycle in October and November but not December and here we are in January and I still haven't had one. I know I'm pregnant but need to know when it happenend. I had sex with an ex in October but had my cycle in November had sex with my boyfriend in November and no cycle in December who is the father

Will need actual dates, what day of the month was the sex in oct, and when was the period in Nov.

For example, if you had sex Oct 30 and period started Nov 1, you could have been pregnant and had a period.

So your info is too vague to give an exact answer.

Normally it would be who you had sex with after Nov period.

Boyfriend!!