I'm so sorry for you. At least you can say goodbye.
When my first snake, Ringo, died, he had been sick for a while, but the veterenary hadn't told me how bad it was and kept telling me it would get better. He was a lightweight one (a corn snake), and had stopped eating, so we couldn't give him a lot of antibiotics. I saw he stopped breathing one evening when I came in, touched him and he came back awake. I called the vet for an urgency. They told me to wait for the morning and bring him in, and that he'd be okay that night. The next morning he died before he could go to the vet.
They (the vet and his assistant) told my grandparents they could've guessed this would happened, but they just couldn't tell me because of how panicky I was. I wish I had had a chance to say goodbye.
I didn't want a new snake or other animal back then, I only wanted him, Ringo. I would've felt guilty "replacing" him. I went so at loss, I got all sick and all, really like I lost a human being. I had an empty terrarium there reminding me of him. Then one of these days my grandma kinda dragged me to the reptile shop. I did then choose a snake, she agreed on paying half of it. I wasn't sure at first but then I decided it would be better. I went for an entirely different species as I _really_ didn't want to replace Ringo. I had always been interested in boas, so that's when I bought a baby one. (small subspecies, doesn't grow over 1m50)
I'm still sorry that it had to go that way. At first I felt like I was "cheating" on Ringo. But I had a little baby snake there of only 3 months old, that needed all my care. For that reason, I couldn't let myself go into drinking and pills. "Someone" needed me. In the meantime, he's like 19 months old and he's grown a lot bigger. I still miss Ringo, when I look at his pictures. But I love him, Calypso, too. He's quite a lot bigger and heavier, and a very good eater, so I feel a bit safer now, but still, you never know. I've already grown attached to him and I couldn't miss him anymore.
Snakes don't really know emotions for humans like dogs and cats do, but they do recognize your smell, and appreciate your warmth (although you shouldn't pick them up every day). And of course we humans do know emotions and affection, luckily, because that's why we take the best care of our pets!