I'm so sorry about this, I didn't post the other day because I didn't want to be the voice of doom, but this is almost exactly what happened with our beloved little dog a couple of years ago. It happened very suddenly, he was very very sick and then couldn't stand up. His back legs kept giving way and his eyes and head were twitching. He could only walk round and round in circles and it was very distressing for both us and him. We rang the vet, who told us to come up in 40 mins. Fortunately hubby was not working on that day, so we sat him on our knees and cuddled him and told him we loved him. When we got to the vet, she took one look at him and said he had had a serious stroke and because of his age (16) it was kindest to let him go. We stayed with him till the end, then brought him home and buried him in his favourite part of the garden. I'm boo hooing my head of as I'm typing this. My heart goes out to you xxxxxx