Hi, I'm sorry for your loss of Nala. I lost my Indi girl one week ago today. She was almost 16, which is good for her breed. I hear the same, too, about a good long life. And I am very, very thankful for a good long life. Like you, I'm not sure how to "adult" without her. If I think of life before her, it was essentially my childhood.
It is excrutiatingly painful to lose a pet regardless of the circumstance. She had a chronic illness, I knew it was coming. She was old, I was supposed to "expect it." Still the grief is crushing for me and my world is upside down.
Allow you and your kids and family to be there for each other. Everyone is on their own grief path, and just being near one another is all that is necessary.
Thank you very much and I'm so sorry for your loss as well. Nala had kidney disease and possibly cancer. She had a great life but the last year we saw a huge decline in her health. And then in the last days she deteriorated rapidly. I knew she only had days or even hours. Today will be super hard because I'm going to be cleaning up her things--cat bed, litter box, etc. :'( Thank you for your condolences.