Birth control or pregnancy or hormones

After not being on te pull for a few months, I started birth control the Sunday after my period. I tok the pill everyday for the next 5 or 6 days and then had unprotected sex. Five days after that I started spotting (more like black old clots). It wasn't a lot but it's been 4 days now and it's becoming more and more. Now it's a lot and a mixture of clots and red blood I think. I only took the pill for 2 weeks so far. Is this normal? Could I be pregnant???! Or is it my body getting use to birth Control again? I'm freaking out. Please help