I have miscarried twice and regardless of the situations it is hurtful. I just have always had to remind myself that there is a reason. Even though I have 4 kids, those 2 still pop in my mind occasionally. I wouldn't worry too much about the diagnosis, unfortunately a pregnancy isn't consider viable until 20 weeks and most dr's wont/cant do anything to prevent a miscarriage. So regardless of his diagnosis, the ending would probably have been the same.
I would definately see my OB and ask questions and read up on what the ER dr suggested. If you do decide to have another baby you would want to know the likelihood of this happening again, etc. Depending on the situation, the dr can take precautions to try to avoid another miscarriage. (for me, I had blood work to check my hormones and if it was low, then I supplemented my hormones to keep them from getting to low and causing me to miscarry.)
Hang in there, hug your babies, and now you know you have a little Angel heaven.