i had my last period on december 1st to december 5th i think. it was the beginning of december, and maybe a week later or sooner i had un protected sex, i usually have irregular periods, but i usually get larger breasts right before my period and i get cramps. its now january 21st i still havent gotten my period, but my breasts have grown a little and i have been getting cramps in my lower stomach and partly in my back, like i would usually get before my period. could i be pregnant or am i just going to start my period?