I can't begin to imagine what you are going through.
One of my colleagues lost her 18 year old son to an accident involving a faulty truck bed, I used to feel bad for her, and I thought I got it. Until I had my son. Upon returning to work and seeing her once more I burst into tears. I got it just enough to know I didn't get it.
Before I had children I found it hard to know what to say to my friends who miscarried. Now that I've had one succesful pregnancy and am well on my way to a second, I still find it hard to know, but I don't refrain from being there. There is a lot of taboo surrounding miscarriage, and most of us tend to put on the kid gloves but I think the important thing to do is just to be there. Whether it's with a bottle of wine, a distracting movie, or just with a big hug, a box of kleenex and a spare few hours. Don't let discomfort stop you from supporting those you love when they need you. I can't imagine it, no, but I know how it feels to have a friend in need and that's when you move mountains to help. Even if helping means providing a warm body to yell at.
I almost didn't write this post. It seemed, in my mind, to take something away from those that had actual experiences to write about. But the point of this is not to stay silent, but to be there no matter how awkward it makes you feel. Don't stay away, don't worry about saying the wrong thing, because nothing is the right thing. For this day of awareness, be aware of people you know, even if you have never known this loss yourself. Be aware and be there.