I'm on my third month of the pill, so I'm not sure if maybe this was caused from just starting the pill, but I'll leave that up to you to decide.
Last month, at the end of my second week of hormones, I started breakthrough bleeding, which seems to happen to me all the time on the pill. Within a few days, the spotting turned into what I like to call the worst period of my life- cramping, headaches, nausea, etc. I bled very heavily: it was thick, clotty, etc. I seriously have never bled like that before. This lasted for about 13 days, and rarely- if ever- became a lighter flow. It let up for like a day before I started my plecebo pills, when I started bleeding again for another two days, but it wasn't as heavy as the days previously, but still noticible and I had to wear tampons, etc. My theory is that I had shed practically all my uterine lining, because God, it was heavy.
At this time, I had been worrying that I was pregnant, despite the fact I always have protected sex (I was mostly worried about fooling around and precum getting on me and miraculously impregnating me). I would have been about two weeks along when this happened, and now I'd be six weeks along if I was actually pregnant. If I had been pregnant at the time, is it possible I could still be after a 13 day heavy flow like that? I'm not noticing any other symptoms of pregnancy, except sensitive nipples (due to the pill, I've gotten that every month, and it seems to be going away for the time being) and nausea if I don't take my pill with a meal.
Good luck to everyone trying!