I Got Intimate With My Bf On 25th Nov For

I got intimate with my bf on 25th Nov for the first time. I was not sure that he ejaculated inside or not so I had taken unwanted 72 within 12 hrs. My period date was 22 dec. But this is 1st Jan today and I have not got periods. I had taken a pregnancy test on 26 Dec , which turned out to be negative. Could I be pregnant? What about my periods?