What Causes Thick And Smelly Vaginal Discharge?

hi.. I ave a really important question to ask.. I recognise a change in my vaginal discharge. the last time i had intercourse, it so happened that my boyfriend ejaculated inside me.. We bought Postinor 2 and i took it. However, i realise that my discharge has had a funny smell for some time now, and the texture of it is more thick. It is still white in color, but i dnt understand the smell. Because of this, im scared to have sex,, since i dnt know if its an STI or an STD. I jus need some professional medical assistance.. Thank u