Here, you need to undergo one blood test
for beta-HCG & TVS scan to rule out implantation
bleeding at the earliest. It is mostly presented with brown discharge. Early pregnancy test is less significant.
Other reasons are vaginal/ pelvic infection
, hormonal imbalance, old endometrial tissue, over wt/ loss, thyroid disturbance, ovarian cyst
, irregular diet habit, stress etc.
Following above test report, you need to consult with gynecologist to undergo other relevant investigations to pinpoint the diagnosis. Take suggestive measure accordingly. Good luck.