Hello, Last year in august of 2012, I had one birth control shot and afterwards, I never went back for another. I skipped a period.Then I bled for 3 months. After that I did not have a period until 5 months later and it was a regular period. Two weeks ago I ended my period and a few days ago I go extreme back cramps, Went to the bathroom and as i wiped, I saw blood. wore a tampon for about 4-6 hours and then it had stopped. Whats a possible explanation for this? I have a history of one misscarriage and a 20 week stillborn birth.