Dark brown discharge instead of my mens. for 5dys, 2dys little 3 heavy enough to soak half of sanitary napin 4-5 same with 1st 2dys what does it mean?

Brown is Blood: Your discharge is probably your period. Brown is just blood that is fully de-oxygenated.

Consult GYN doctor: Dark brown discharge could have been menses , old clotted blood collected in uterus . for a1or2 days Since you are constipated and there is pressure of fecal mass on uterus and vagina .IFyou do not have any other problem , or no h/o injury to genitalia and no more discharge then wait for your next menses .If any such discharge recurs, or still worried then better see GYN doctor .