I just started my period yesterday, and I've been on birth control since 2008. My prescription has changed a few times, but I've taken it for years and had regular periods. However, earlier today I had some pretty bad cramps, so I took my tampon out and they got better. I rarely have any cramps during my periods, so it was a bit out of the ordinary. I haven't had any cramps for a few hours, but I went to the bathroom, and when I used the toilet tissue, there was a sac-like membrane with a red, string-like connected to it. I've seen this described as an early miscarriage (my fiancé and I last had sex two weeks ago, and he also wore a condom) but others say it could be a uterine cast or just clots/uterine wall. It was fairly large, the sac looked like it was broken in half and together was about the size of a half dollar and the "string" was about 2 inches or so. I'm in no pain whatsoever. Any clues? Should I go see a doctor?