what's goen on?

So, the thing is that i had unprotected sex with my boyfriend,after that i took morning after pill (i've done that on time and that was my firts time when i was using that).....after 2 weeks my period starts(23 december till 4th january),  and they was 2 weeks early then usually.....cause usually my period starts on the 9th date of each month.......!
From the morning i don't feel sick , i would say that i havn't got pregnancy symptoms. (and after every 4-7 days i hav a back ach, how it is always before periods.
But my question 2 u is,when my period gonna starts again.....because 2day is 2nd february and i am a bit comfused?!