Pill Effectiveness

I have been the pill for almost 10 years now. I have changed the brand once in the amount of time that I have been on it. I have also been with my current boyfriend for a little over two months..we don't have sex often but one day I stayed the night and we had unprotected sex twice in one day..it wasn't planned and was just in the heat of the moment.. Is it possible for it to possibly increase the chance of getting pregnant even though I am on the pill??