Hi thanks for your question.
You had unprotected sex on 23rd of september and you had your periods after that.There is nothing to worry, you are not pregnant.Actually menstrual cycle get disturbed after emergency
contraception.Bleeding for 8 days after postinor -2 was side effect of emergency contraception.Next cycle of 49 days wich was on 5th of December was disturbed cycle due to emergency contraception.Your next cycle is over due by 7 days is also disturbed due to effect of emergency contraception.There is nothing to worry,hopefully your cycle will get normalized in next few months
Hope this answers your question.