Help!

I'm trying to make this story short. On 30 may i had sex for the first time. Some days before that i decided to continue with the pill because otherwise i would be on my period on my birthday (so i skipped my period). On the 27th i began taking the pill the same time each day (because my dumb ass didn't even know you should do that). And maybe a couple of days after that i began to have very sore breasts, like only on the inside. And they have grown a bit too, so now i'm quite scared i'm pregnant and i'm only 17. Could there be a possibility?