Can Birth Control Pills Cause Cramps?

i am on the control pill, but my dosage pattern has been very inconsistant, i was taking the pill more like a morning after pill where i would only take them after sex - 2 or 3 at a time or when i want to stop my period. This is my 8th day disharging old blood, not smelly though and i am suffering light cramps in my tummy, What is going on, when will it stop, how can i stop it?