Hello doctor i am pregnant now 8 week and 4 day...

Treatment of brown vaginal discharge in early pregnancy:
In fact, brown vaginal discharge in early pregnancy may be an urgent condition that requires a medical examination. Therefore, it's recommended to visit the nearest medical center to have a full assessment by the gyne & obs. specialist in order to take the appropriate actions based on the diagnosis. If it's an abortion, there will be three ways for treatment which include an expectant management, which means waiting for the fetus to come out on its own, taking some medications that help expel the pregnancy tissue, and a surgical treatment through curettage (D&C) after excluding any other causes.
Please note, that this bleeding also might result from the implantation of the fertilized ovum into the uterus which can lead to some blood spot. However, to be sure about your situation, you need to be checked by the doctor. 

Diagnosis:
History and medical examination to be done by the specialist doctor to check your condition. CBC and BHCG test to check the level of pregnancy hormone. Cervical examination as well as abdominal ultrasound.

What are the possible causes?
1. Abortion
2. Ectopic pregnancy
3. Molar pregnancy

Recommendation:
It's recommended to visit the nearest medical center for further assessment and management.