I have never felt a heartache as heavy as this. My little dog is dying in front of my eyes and there is nothing I can do. How do I stop feeling like this?

She’s been my best friend for 16 years and i can’t remember life without her. I love her so, so much I can’t describe. I know it’s her time to go and she has had a wonderful life, but I can’t stop wanting her to live. Can someone please offer me advice or show me photos of your pets to try and cheer me up?