"I decided to have a baby on my own. Because it's all I've ever wanted and life is short," she wrote.
"To get pregnant was a miracle in itself and an experience I will never forget and I know I will have again.
"I'm still in shock, the sadness is overwhelming. But I know I am strong, and I know I will be OK."
She added: "I also know millions of women all over the world have felt this pain and way worse. I feel connected to those of you I know and those of you I don't.
"It's the loneliest feeling in the world."