Aly, it is time. You know it, Peka knows it, God knows it. Since you love her best, you must be the one to set her free, BECAUSE you love her. As you've described, Peka's quality of life has failed. No matter how much we hate for that to happen, it still does. That's life.... and sadly, death. You have given Peka, in the the short time that you've had her, the love of a lifetime! If it weren't for you, she would have never known love. She may act aloof because she never knew love before you came along and never learned how to accept it and give it back. Maybe she doesn't like to be held because she hurts. In her way, she loves you very much and knows you love her.
It is time now. If you cannot be with her, she will not fault you. Being present at the final moments takes an unbearable amount of strength that sometimes just can't be suffered. She will still love you. It doesn't mean that you love her less. No one blames you. Don't ever think that anyone does.
My thoughts and prayers will be with you and Peka tomorrow. Soon she will be painfree and running with the best of them at the PetTalk area of Rainbow Bridge. Hugs.