I saw Death around the corner

We lost one of our dogs on Thursday.  I knew she was sick and hoped to get her to the vet Thursday but we were too late.  All the signs were there but I chose not to act because I felt we could not afford a vet visit.  Granted the dog was old, I thought part of her behavior was just related to her age.  Normally she would go outside every morning with the other dog to use the bathroom but for the last week or so she would not.  She chose to pee in the house in various spots.  She was not eating or drinking water.  The tell-tale sign that should have jumped out at me is that she was throwing up.  She was so sick that when she did throw up, she wouldn't even move from the spot.  She just laid there.  The kids are aware of our loss.  The 3yr old was told by my wife that the dog is gone to be with God.  The other 2 are old enough to understand death and are dealing with it.  I regret losing that dog.  I regret seeing Death around the corner and not being able to stop it.