I have that for a week now..at first it was light reddish with light brown..but two days ago its started to get darker. And its not after sex.
It may be because your cervix is irritated after sex? If you're really worried I would call your doctor and they can give you a better diagnosis
Honestly .. I Been Having Unprotected Sex Sence I've Became Pregnant & I Havent Had Any Brown Discharge Or Any Color Besides White & Clear Discharge After Sex , Usually The Sperm Comes Right Out .. I Think You Should Let Your Docter Know , Just Incase
Its normal to happen after sex don't worry I experience it as well. Nothing to stress about