What Causes Cramping And Brown Vaginal Discharge After Taking Contraceptive Pill?

I took the next choice pill and followed all the directions correctly. 6 Days later I am experiancing cramping, like menstral cramping and discharge...However the discharge is not like menstral discharge...It started brown with a red tinge then it came out to bright red blood, like a wound would bleed. No mucus like stufff in it really. The iron smell is alot stronger than menstral flow also..Is there something seriously wrong???