i have discharge while on the shot?

Ophelia

on january 27 i got the depo shot, bout wasn’t on birth control for 2 weeks before that. my boyfriend and i had sex 3 times during those 2 weeks but one days where my risk for pregnancy was very low. i didn’t get a period February, and now i’m getting brown discharge. it’s my first time on the depo shot, so is this normal??? PLEASE HELP