Plan B or pregnancy?

I had my cycle on the 4th of September. That following Saturday me and my boyfriend had unprotected sex and he had came in me and i had went and got a plan b on that Sunday and a week later i was experiencing bleeding (pink/brownish ) then Two days later it was heavy bleeding for about another 2 days . But my cycle is suppose to start on September 28th . So with that being said did i start my cycle early due to the plan b or am i pregnant since i haven’t gotten my period that’s suppose to start on the 28th?