As your symptoms suggest, it looks like you are having some hormonal
imbalance,because brown discharge is seen during a breakthrough bleed. Yet, a pregnancy
test soon after a missed period may not be positive. You should repeat the test, 3-7 days after the missed period and contact your doctor for further suggestions. If you wish for a better confirmation, you may get a serum beta-hCG
assay and a trans-vaginal sonogram.Take care.