Multiple miscarriages

My husband and I have been ttc since February 2013. Last August at my 10 week appointment I found out I had a missed miscarriage and had to have a d&c done. The baby's heart had stopped at 7 weeks when we had seen it in an ultrasound just a week earlier. In December I found out I was pregnant again. The week I was supposed to have my first appointment, which I think should have put me at 7 weeks again, I miscarried. My doctor is adamant that the two are completely unrelated, but I'm not convinced. With the last miscarriage, I felt that she was completely dismissing all of our concerns and questions. I have an appointment with a new doctor tomorrow to talk about our options for testing, plans for future pregnancies, etc. I know you can't expect many answers when it comes to miscarriage, but I'm terrified there is a serious issue and want to prevent this from happening again... Have any of you had multiple miscarriages and what did your doctor suggest? Thanks for ANY input, ladies.