Could I be pregnant?

B
I know I'm probably just paranoid, but I had sex on November 25 and the last time before that was sometime in May, I got my period in December but it was a weird period. I was on the pill for a while but stopped taking it because of the side affects. Anyways, I was just seeking some advice or honest opinions. 
I'm a college student and my semester started not too long ago.but usually my period isn't late! Help