What Causes Brown And Black Discharge Before And After Periods?

Hi, im 23 years old for about 6 months i have been having a brown/black discharge for about 4 days before my period starts and also for a while after my period goes. when i am actually bleeding my period seems normal but the before and after doesnt. i have acne ..again its not sever but it seems to be getting worse on my cheeks. i have bled after sex twice in the last two months. my husband and i started trying for a baby this month i didnt think anything of these symptoms until now but the dark brown/black discharge is worse than its ever been so im getting concerned.