Did I miscarry? Doctors can't explain (Kinda long)?

This was two years ago, but I'm still curious because no one has been able to give me an explanation. Okay, so in the beginning of November 2008 I was pregnant and my EDD was August 23, 2009. Two weeks later I was experiencing bleeding and the most HORRIBLE cramps ever. I went to the ER and they did an u/s and checked my cervix, they said my cervix was open and that I was miscarrying and to go home and it would come out on its own. Sure enough a couple days later, what I think was the fetus came out when I was going to the bathroom. (Horrifying :[) About 2 wks later I still felt pregnant (bf and i had not had sex since bf m/c) so i took a hpt and it was positive?! The nurse said its just the hormones left from the previous pregnancy but just to be sure to come in for some testing. 1 wk later I went in and was indeed pregnant and given a new due date of September 3rd. Well my daughter was born August 15, almost a month early and a few days before the old due date. Did I actually have a m/c? Could it have been twins and only one died? Anyone experience anything like this cuz i'm confused!!!