Oh Expat I am so so sorry. I wish there was something more I could say other than you have my deepest sympathy. That is every parents worst nightmare. 
This thread is fascinating and very emotional. I think you're all so brave for as a previous poster said, admitting that you wished you'd never had children is almost the last taboo. When I had my first, much wanted DS, I found the early months to be awful. I'd studied something called 'Altered Body Image' as a student; this occurs when someone views themselves differently (and negatively) after something changes about them, usually physically eg an amputation, a stoma, burns etc. I felt as though I had 'Altered Life Image'. Not only had my body changed, I'd put on weight, my boobs were mahoosive, I'd had a 2nd degree tear, but every facet of my life had changed - I now had this tiny baby to care for, my life wasn't about me anymore. Thankfully it did get better and I now have 3 DSs but I'll never forget those early months with my first.
An earlier poster said that those who don't feel that they're cut out for the baby / toddler years may find themselves to be brilliant with teenagers. This was certainly the case for a close friend of mine and DHs: she was a secondary school teacher who came from a big, close Italian family. She couldn't wait to have children and was also lucky enough to have a lovely caring DH. However, she hated, really hated, having a baby or a young child. She was on anti depressants, had counselling, the lot. She went from a bright, extrovert woman into a nervy shadow of her former self. But! She was fabulous with the so-called difficult teenage years! When most of her friends, who she'd put on a pedestal in the early years were tearing their hair out, she was the one with the answers. It was lovely
and I know who I'll be asking for advice when my lot hit the teenage years.
I really hope I'm not rambling too much; I truly think that us mums are our own worst critics and I just wanted to share this story. I wish all of you / us the very best. It's bloody hard work this parenting lark