Please answer me?

Im currently 8 weeks pregnant my first baby. I noticed after I have sex, when I wipe myself to clean up there was some type of discharge it looked like a dark brown type. Is it normal? Every now & then when I wipe I see a bit of brown but not a lot , it comes and goes . I don't feel pain or anything, I get mild cramps randomly but nothing out of the ordinary I'm scheduled for an appointment next month. When I went to my doctor the first time a few weeks ago he said everything was fine , I even heard the baby's heartbeat really fast and active too . I'm just concerned . Please don't judge