Can you still be pregnant after your period??

So I started my period 3 days sooner then I was suppose to. It was kinda light the first day then a little more on the second day and now it’s like just brown and like nothing at all. I only had cramps for one day as well. I’ve felt nauseous and my periods usually last 4-5 days. So this is kinda irregular for me. Is there still a possibility I might be pregnant or not?? Thanks!