Yes, I am numb, in shock and I can feel the bitterness growing

Everything does not happen for a reason.  Why then would I have lost two babies, and my job in less than 6 months?  Today at a routine appointment (to do face and heart measurements as a follow up to the anatomy scan, which was perfect and normal), we learned that at some point today Rango's heart stopped beating.  He was moving yesterday, and had a heartbeat (we listened after dinner).  And all the growth measurements have him at his gestational age, 21w5d.  All the doctors said (after getting ultrasounds done) that he was perfectly healthy and were completely perplexed as to what happened.
Why can't I give my husband a live son?  Why can't I make it past 21weeks in a pregnancy?  Why do I have to bury another child?  And why, why, did we have to find out again with both girls in the room (like last time)?
I am in shock, and am mainly upset that I am a failure, and something is so utterly wrong with me that I cannot have a live child.
I have so many thoughts swirling in my head.  None of them are good.  It doesn't make sense, and its not fair.  And I don't want to hear life's not fair.  Why does everyone else around me get to have healthy pregnancies, again, and I am facing my second d & e on wednesday?
I just want my baby!!!