I Had Unprotected Intercourse Last Saturday And My Boyfriend Ejaculated

I had unprotected intercourse last Saturday and my boyfriend ejaculated three times in me ... the other day I took postinor2 and when i woke up the other morning after taking it j realised some yellow vaginal discharge from then to now ... what causes that .. and I'm not having any pain there to say it's a yeast but it does smells weird ...?