HELP IS THIS NORMAL?? PLEASE EVERYONE READ AND ANSWER!?

I'm 3 months pregnant and I'm having a brownish tanish color discharge stain on my undies. I have to change a lot. Its Not brown like old blood. Also I get yellow discharge stains too. Ive been tested for STDs and even bacteria vaginosis too but I Don't have nothing! Idk what to do, I bother my doc a lot! Is my baby ok??