What Causes Flat Black Flakes From Anus?

I'm finding aflat black flakes on the toilet paper when I wipe which appear to be from my bottom( I'm female) sometimes hard black lumps drop out of my pants, am worried as these apear to be coming from my bottom even when i haven't been to the toilet, just noticced the black flakes on a flannel after washing my bottom. am worries, hop ethat makes sense, thanks