How do I change this

So my dog is 8, almost 9 and I’m sooo depressed about it. He’s perfectly healthy, happy and so loved. My parents and I got him before I got married so when he was 4 I got married moved 2 hours away. He’s my everything but I didn’t take him because that was his home I moved into an apt and he’s super attached to my mom. But idk how to get over the daily anxiety that he won’t be here one day in the future. Like how can I be hopeful about a future without him? I’m depressed very night and every morning because that’s one more day gone of his life.... it’s really consuming my life 😭