I am sorry, so very sorry.
We had Polli let go at our home, on her bed, surrounded by us and her pack. They knew. They all came to say good bye. They were sad for a few days, quiet, subdued but back to "normal" (and I do use that word loosely here ) within a few days.
I was very relieved to be able to do it at home. Polli stressed horribly at the vet. I did not want that to be the last thing she remembered.
Sigh. I wish there was something I could say to make it better for you.