whats going on?

i started birth control last sunday, i had protected sex two days before my period, got my period normally and havent had sex, i started the birth control the sunday my period stopped and havent been active since before my period, im constipated, have sore breasts, my appetite is changing, my sex drive isnt all there, and im constantly peeing, is there a chance of pregnancy? or is this side effects from the bc?