I’m so lost

I’m at a total loss right now. My 10 year old lab mix was in the backyard on December 31st running around with her tail up, galloping, barking at people walking by… it was a normal thing for her to do. Earlier that morning she snuggled up to me in bed and then I got out of the shower she came and sat next to me, all normal. 9:15 AM she is having her normal backyard behavior as mentioned above and at 9:45 my wife and I find her laying in her dog run, passed away. She was laying on her side next to the AC units, eyes open, tongue out, gone for likely 20 minutes or so.

She was one of my best friends, I truly loved her. We rescued her as a puppy, she was found tied to a tee with cigarette burns all over her and despite that she was the sweetest most playful girl. I am happy we were able to give her a good life but now I’m lost… she seemed fine and I looked at the cameras, she went from playing to gone in a blink and I have no answers.

I’m so lost without my baby girl right now and I can’t stop thinking about the most loving dog in the world who ALWAYS wanted to be around us, dying alone outside.

How do I cope with this? I won’t ever have answers to the cause as she has gone for cremation.