Hello,
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The possibility of pregnancy in your case seems to be less as you had unprotected intercourse during the periods(on 3rd day)and it is usually considered a safe period.Also you had taken I pill after that within the stipulated time.I pill is an emergency contraceptive pill and being high in hormones it can cause delayed next period and few irregular cycles.It seems you are also experiencing that.
Relax as stress can further delay them.The periods might start in a week time.Regarding the contact you had on 27Dec that also would have no chances of pregnancy as immediately after that you had periods.
Kindly avoid stress and wait for the periods to start.If they do not start even after a week consider repeating the test and visit a Gynaecologist for evaluation.
Take care!