So, so sorry for you loss! My Rosie was hit by a garbage truck the same way. Died instantly. I didn't see, but my husband and son did. My son did as you did...he collapsed. My
Rosie was my heart and soul. We had her 10 1/2 beautiful years and lost her almost 1 year ago October 17. My heart still breaks. The one consolation is that it happened instantly as it did for your Mable. Until that moment she was a happy little dog and knew she was loved. Never forget that. I never had the chance to say goodbye to my girl right after it happened because I was at work an hour away. It will hurt for a very long time, but it does get better. We got a puppy a few months after my Rosie passed. He is a joy and holds a different place in my heart. You too will mend. Hugs and prayers..... You will meet once again!