pains in the stomache with cramping on birthcontrol

i would really appreciate it if someone answered this one...ever since i started taking birth control, i get cramps like i'm going to start my period in between my period..for example right now..i just finished my period on tuesday and today i have pains in my lower abs like im going to start my period again..i know that i just had my period but can that be signs of an early pregnancy? (i know thats dumb but i kinda worry) my period is normal and always on time so i dont have problems with that..does any one know?