HELP!! Need an advice!!!

Nelly

I got what I considered my Period, it stoped on the 21 of September on the 22 I had sex and he finish inside. The next day I woke up and use the restroom when I wiped there was brown discharge. And since then I’ve been having brown discharge. And it hasn’t stopped. Ik this is not implantation bleeding. Has this happen to any one? Forgot to mention. The in August my period lasted for 8 days. In September was 4 but I’m still having the brown blood/Discharge. If comes and goes. And only can see it if I wiped. Having a lil of cramping. Any suggestions on what might be wrong? Should I be worry if I’m pregnant? Or having a miscarriage? 😒