According to the symptoms you describe (brown discharge and vaginal bleeding after your period), it seems that you have some type of uterine bleeding (spotting or metrorrhagia). Bleeding from the uterus that is not caused by menstruation is called "metrorrhagia", or spotting. Spotting can be functional or organic. Functional spotting is due to a disbalance of the sexual hormones (estrogen and progesterone). A drop of hormonal levels usually causes functional bleeding. You can ask for diagnostic examinations from your gynecologist.
Organic spotting may be due to a condition in the uterus such as an infection, tumor (malignant or benign), miscarriage, ectopic pregnancy, etc. You can visit your gynecologist to request examinations.