K.L.
Oh hun, I have so been there. The things we do for our pets. Here's my story: Old labrador, enlarged spleen so he couldn't run or play rough. Breathing problems, so we airconditioned THE GARAGE since he had too many accidents in the house and we moved him to the garage. He had a hard time with warmer weather. We knew it was time to help him go when he collapsed on a lovely May day (2 years ago), about 55 degrees-he was too hot. Fortunately I was outside with him. We decided that it was better to make the kind decision to put him down, rather than have him suffer and possibly die alone and stressed, scared, and hurting. We were able to find a vet that came to our house for the last injection. The kids got to say goodbye, rather than come home and find him gone. My husband and I were with him--feeding him treats to the end.
Listen to your heart. Dogs don't know today from tomorrow. They can't plan for the future or want to be there for the next trip to the park. They just know now. How is her "now?" If her now is good, and she is still enjoying life, and you can put up with the caregiving, then keep on keeping on. Only you can know when it is right. Just make the best decision you can in the moment. I know friends who look back and say they waited too long because the pet really was suffering. Good luck to you.