vaginapagina | Vagina as tar filter?

Okay, this is going to sound a little bit out there but it's the only thing I can think of to make sense of this. In the last week or so I've been having brown discharge, almost like very oxidized spotting..but not. I was able to keggle quite a bit of it out today, but it looked more like flem from a really bad cold more than blood. I've thought about what in the world it could be - I'm on birth control (and near the end of the three weeks, so it's kind of unlikely for it to be really old blood), but I am taking anti-malarial drugs (I'm studying abroad), but it seems unlikely that it would cause something now after being on them for two months. My diet and water source changed radically, but again, that's two months ago, going on three. The only thing I can think of is in the last week I've been smoking socially (normally I don't, at all) and that my body is processing the chemicals and tar and trying to flush it out of my system anyway that it can. Has this happened to anyone else? Insight? I mean, I know cigarettes are bad for you (obviously), but damn. Who knew.