I'm sorry for your loss. After 3 early m/c's I have done lots of research. One thing I did come across was that most women who have had 1 or 2 miscarriages and are under 35 will go on to have a healthy baby without any treatment at all. I think that's why most doctors wont start to investigate m/c's until you've had 3, but some will. If however you are over 35 (like me) then you have around a 50/50 chance with each pregnancy.

I am in the investigation stage at the moment but my gyno thinks the last two were caused by what looks like a fibroid and I am waiting for a lap to have this dealt with.

You can't judge anything by the lack of morning sickness or other symptoms as some women don't get it at all and go on to have healthy babies. In my last short lived pregnancy my symptoms were quite strong compared to other ladies that were just finding out they were pregnant but my HCG levels turned out to be low and I m/c but those ladies are still pregnant.

There is a thread on here somewhere that tells you what tests to ask for, I suggest you have a read of it.