My poop was very light brown and very dark brown (i just increased my dose of iron slightly) in the same stool today. I was already tested for stomach pain and murky, foul smelling urine but they didn't find anything. Should I be concerned?I'm 31, female, 155lbs, on quite a bit of medication(mostly for mood and sleep), and had my gallbladder out this past spring with no complications. My stomach is hurting today, but not as badly as last week.