I'm 16 and pregnant.

I'm 16 too and I am not sure if i am prego or not and like I had sex without protection and my bf believes that he cummed out side and pulled his penis out like 10mins before he cum and he told me that i am not gonna get pregnant. Problem is that i missed my period for 3days, i don't know if thats mean im still gonna get pregnant. i dunno what to do. my bf is  leaving me and has replaced me with someone else and thought that hes doing it coz he doesn't want to make argument with my family. Yeah I know he is such an unresponsible guy!
HELLLPPP!

what pills did you take ?