Miscarried twin girls ttc ?

I miscarried my twin girls the 25/05/11 at 18 weeks 6weeks ago I'm desperate to get pregnant again but have no clue when I ovulated I was checking my cm but was very hard to gauge,I bled for 2 weeks then it stopped but the a week after on the 19/06/11 It stopped I started having a discharge that was brown wit some small clots then it went to a very light pink then brown again finally it stopped on 27/06/11 had a lot of cramping while this was happening I had this ongoing for about a week and a half along with hot flushes and bloating!!so I get excited and have done several hpt all neg:-( could that have been my period or implantation bleeding or could I be testing too early as I dont know when my period is due???has anyone any ideas going mad here wondering I just think getting pregnant will not only make me and my partner over the moon but will help me look to the future instead of looking back at what happened!!!labour was induced with medication babies delivered and afterbirth no d&c the twins died due to twin to twin transfusion