Is there a possibility?

I had sex on CD 12 and a lot of symptoms of pregnancy these past couple of weeks, i tested at 7DPO, 8DPO and one day before my missed period and they were all negative. I got my period on the 12th instead of the 11th but itsonly been three day and my period looks like it’s going off.. which is pretty unusual because my periods are normal and they ALWAYS last 5 days. So now I’m a little confused, is there a possibility i could still be pregnant?