Brown discharge/spotting for 3 weeks

Please HELP! I'm 12 weeks pregnant ( it's my 3rd pregnancy) but the first time I have so much bleeding discharge going on inside AND it's every day. Starting from week 8 until today I see brown (old blood) discharge. I called my family doctor the office send me to the nearest emergency room. I've been to the emergency room for 3 times, they say it's not a miscarriage and my blood work is excellent, the baby is ok (for now) the bleeding is going behind the placenta and they send me back to the family doctor. The first Gynecologist appointment is more than a month away. But I'm really worried, doesn't understand what causes the bleeding and how can I stop it before it's too late. Maybe someone experience similar thing and have some advice. Thanks a lot in advance.