BIG HUGS
I am very sorry but you have made the kindest and most loving decision. We all want to give our piggies the best and happiest of lives but sometimes that is just not possible and all we can do is spare a beloved one a further life that will never be free of major pain or a slow decline from there won't be a return.
I made similar decision for my Iola when several issues added up to a very unhappy total and my vet couldn't guarantee me more than 1-8 weeks on very expensive but essentially not very effective medication. Since was already increasingly losing use of her back legs and kept falling over, I decided to call it shots for her there and then. I am glad I did - it was right at the start of the long 2018 heat wave; not something to face when one of her other problems was kidney failure. The heat was already putting extra pressure on her failing body.
It's never a gift we want to make but it can be the only one and at the same time the most loving gift we can give.
You know in your heart when the time has come. It has been a very brave fight you have fought on behalf of Pumpkin and you have bought her quite a lot of extra time with your dedicated care. Pumpkin knew that she was loved, treasured and in the best possible home.
Be kind with yourself and give yourself time to stop and rest. The pain of the loss is greater when you have created such a close bond through your care but be also very proud of yourself. You have not failed Pumpkin in any way and at any stage.