Could've, Should've, Would've

Four years ago, I went to the emergency room with severe chest pains, at the age of seventeen. After an MRI was done, it was determined that I had three blood clots in my left lung and one in my right. At the time, I was on YAZ birth control and was told that is what caused the clots and that I'd have to be watched very closely if I were ever to become pregnant and that I had to be incredibly cautious taking birth control.
After being hospitalized, I was put on Lovenox injections (shots I gave myself daily) for 4 months and then on Coumadin for 6. When I became pregnant last year, I had advised my OB/GYN that I had a history of blood clots, and that my father has had them in the past as well. He sent me to a hemotologist to have my blood tested and my OB saw "no reason for me to be on blood thinners." He seemed so unconcerned. Since my son had passed away a few days before birth, they weren't able to tell if the clots in my placenta were pre or post-death. He was incredibly small for his age, weighing only 15 ounces. He should have been twice that. And my placenta measured 5 weeks too small.
I went to a Fetal Maternal Medicine Specialist yesterday, I am desperate for answers. He is almost certain that my Kyler died due to a blood clotting disorder. He thought it to be absurd that I was not placed on medication. I am LIVID! I trusted my doctor throughout my pregnancy, I trusted him with the life of my unborn child and I feel so let down. I wish I had done more research and paid closer attention. Unfortunately, there is no way of knowing whether or not my son would still be here if I had been put on blood thinners, but I can't help but wonder. How can I trust any doctor again? I just don't know what to do with this. I should have pushed for them to put me on medication. I am beyond devastated.
The specialist also advised me that because I have suffered a late term loss, I am twice as likely to lose another child as someone who has had no previous losses. I cannot and will not go through this again.
Fortunately, there is hope at the end of this very, very dark tunnel. He let me know that once I do become pregnant again, he will immediately prescribe me medication to prevent clots. It's hard for me to imagine ever having a healthy baby. Honestly, I would be more surprised to have a healthy baby than to have another loss. I just can't wait to wake up from this nightmare. Now, not only is my baby dead, but I'm pretty certain his death could have been prevented.