Puppy lost

How long does it take to get over the death of a puppy. It’s going on two years and i still am depressed and blaming myself. He got sick and i instantly realized it was parvo and the same night he passed. I feel like it’s so much worse because his mom is my moms dog. I was there when he was born and actually had to help get him breathing. Any advice on how to move on would be greatly appreciated. Thanks!