I got goosebumps reading your post.
Me and my husband just went through this same exact thing.
Our dog got sick out of no where and we thought she was diabetic so we took her to the vet Monday night. We left her there a few days to be hooked up to IV Fluids/Antibiotics and given insulin. Wednesday night we go to see her and my sister (she's a vet tech) tells me her blood test is showing she is having liver failure and it could be caused by a tumor or some sort of cancer. We were told her levels were so high there was no reversing the damage that was already done to her liver and pancreas. Wednesday night we had to make the decision to euthanize her.
I think I have fallen into a depression because of it. I keep thinking about the what ifs and if there were any signs I missed. It's been a few days now and it's getting easier but it just takes time. Talking about her and the memories I had of her helps a lot. Me and my husband cry together too. We talk about the good times, our plans for her ashes, etc.
I hope this helps you and I'm so sorry about your loss. You're not alone
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