where is my period?? 😦😦

Hi guys so my 2016 has been been pretty crazy so I keep a planner to track my periods. It seems as though it has slipped my mind to track my October & November periods but I remember having both and how long they stayed. 
I tried to do better in December and wrote it down. 
Since then I've had sex and I've been have the same ol' normal symptoms youd normally would get on a period. Boobs swollen and tender, occasional cramps, and acne breakouts 🙄
But it's January 3rd and last month it came dec 1st and stayed till dec 7th I am worried. 😭