Devastated

Gemma • Pregnant with rainbow baby and it's a boy. Two children at home 8 & 10
I started spotting two days ago, this morning I'm bleeding heavily. I'm so sad. I know what will be will be but I'm finding it hard to understand. I keep thinking of reasons as to why it's happened. Did I do something wrong? I lifted some heavy laundry the other day, and I was picking up my friends 3 yr old. Was it that?