Bleeding on the Pill

[diamondxavenue.livejournal.com]

I just finished my last active pill of the month yesterday. I've been on it for 9 months. However, on Tuesday evening I had discharge with a long streak of fresh red blood in it - about the width of a hair. Then yesterday morning, my discharge was brown as if it contained dried blood. Tuesday I had experienced a stingy feeling, so I figured I'd somehow scratched something internally. But then last night I had sudden discharge with period-colored blood in it. There was no blood this morning (I used a tampon). I took a pregnancy test about two weeks ago and it was negative.

Last time I was supposed to have my pill-withdrawal period, I traveled and thus it was late by a few days; my guess is that there was still some period blood left over that got stuck when I started the new cycle and my body couldn't hold it anymore, but that doesn't make sense given the relative freshness of the blood. Besides that, what could it be?