I remember the exact week it stopped being normal.
My 14-year-old boy Leo stopped playing. Overnight. Like his body made a decision without telling him. He stopped waiting at the front door when I got home. He stopped dragging his feather toy across the carpet. He stopped eating properly. He would sniff the bowl, take a mouthful or two, then walk away and find a corner. Every single day I would find him lying completely flat on his side on the rug, or squeezed behind the guest bathroom toilet with his face pressed against the wall. His 20-hour sleep cycles felt less like resting and more like rehearsal.
I rushed him to the emergency clinic and spent nearly $400 on a full blood panel. When the vet finally came back she looked at the clipboard and said: "His panels are totally clean. It's just old age."
I drove home and cried in the driveway for twenty minutes. It felt like a death sentence handed to someone who didn't know what they'd done wrong.