I always have unprotected sex with my boyfriend . i had sex two days ago and after it started to smell and i have light brown discharge. my period is in a couple days . what could this be ?

Period or infection: early start of period can cause brown discharge any itch color of discharge if smell persists after period it could be infection

Birth control: Please, if you are not prepared to have a baby, stop having unprotected sex! Call your doctor to get on birth control. He/she can likely also answer your question about your brown discharge.

Infection: I strongly suspect sexual transmitted disease, not period related symptoms. You needs treatment as soon as possible.