I ended my period 5 days ago and got brown blood on the 5th day why?

Normal: This is just old blood that didn't come down from uterus/cervix at the same time as the redder blood. Noithing's wrong and there's nothing to worry about. Hope that helps!

Unlikely Dangerous!: During periods, we shed the inner lining of the uterus -- the endometrium -- if we're not pregnant. Sometimes that shed layer may not come out for a day or two ; can turn brown. So can be normal; why it changed, i can't say. If you are having low pelvic pain, the discharge is unusually foul smelling, or your have a fever, though, it could be an infection -- then see an ob/gyn! good luck!