(Another) question about Microgestin Fe 1/20

When I first went on this BC pill in April, I researched it and read a lot of horrible things - that it caused severe mood swings, weight gain, loss of libido, loss of appetite, and extreme breast sensitivity. Thankfully, none of those things happened to me and I have been very happy with this pill, but something weird's going on lately.

Another common side effect is spotting between periods. Well, I have mild endometriosis and had horribly heavy periods for years, even though I was always on a BC pill (Ortho TriCyclen, mostly). So I take this pill differently than most. I skip the placebo pills in three pill packs and then have my period while taking the fourth pack. I spotted a very little bit for a couple months while getting used to not having a period every month, but it was no big deal.

Two weeks ago, I got my "period". It lasted for about three days and was very light. I had almost no cramping.

I'm currently on active pills. Last Wednesday, I had intercourse for the first time since starting this pill. The following morning, I noticed some spotting. The next day it was heavier and more reddish (before, it had been mostly brown... sorry for describing it). Three days later I am bleeding more than I ever have since beginning this pill, and am having very bad cramping, especially in my back. I have not missed a pill, nor have I taken it later than I usually do. Could this be from having sex? The act wasn't particularly rough or anything. I hadn't had sex for about 6.5 months until then. Has anyone had this happen to them?

When you first start BC your cycle can do flip flops. If your getting ready to start your cycle, having intercourse can help with that process. I think that your body is trying to adjust to the BC.