A brownish discharge during your period could be a symptom of something more serious. The most likely cause of a brownish discharge could be pregnancy itself.
This is because the very first symptoms of pregnancy is the Implantation bleeding. This is a pinkish brown discharge that mostly every woman experiences at first when she conceives. So you better watch out. Take a home pregnancy test as soon as possible. If it does not show anything, check out with a doctor. This is very important because early detection of pregnancy can save you from many complications of pregnancy.