What could it be?

Ok so on Decembe 22 I was intimate with my boyfriend and it was the day before my calendar says I ovulate and we did not use protection. On January I started cramping a week before my period and a week after which is not normal for me plus I was a day late. This month I've just been really nauseous and super moody and all I want to do is sleep and I got my period aswell but it seemed a bit lighter than usual and I was a day late aswell. Is there a chance I could be pregnant and still bleed! Or am i thinking too much about this!