Possibility of pregnancy

Hi I'm 16 nearly 17 years old and me and my partner had in protective sex however I did not feel that him came/ cummed inside me however I've started to get milky/white runny discharge just this week however I'm supposed to be starting my period in 4 days is it because I'm due for my period , also if I do have my period in 4 days does this mean I won't be pregnant :)