Have Cat Questions? Ask a Cat Vet Online.
I'm sorry, I can't do a phone call at this time, but I would be glad to answer your question.
I'm so sorry to hear this sad news about your beloved kitty's condition. The most humane and painless decision, would be to have her euthanized at an ER vet center, tonight, so she doesn't have to suffer any longer. I would not recommend giving her the medications you mentioned, as the vet has a set protocol to make this as easy as possible for her, although I know this is not an easy time for either of you. It might cost a little more than your regular vet, but if she were mine, this is the route I would take.
I hope you will consider this, and you are very selfless to want to end your beloved kitty's suffering by making the right decision, out of your love for her!
My heart and best thoughts and prayers go out to you and your kitty.