my 10 year old border collie developed this last week. I took her a walk and she sat on the walk and then was sick twice, didn't want to walk and then we walked home. She then became rapidly worse :( and was drinking water (clever) and just bringing it all back. Luckily vet got her in straight away but she had to go into hospital for two days as they thought it might be toxic poisoning (as we live on farmland) or pancreatis, or something more sinister, thankfully it wasn't and once re hydrated and on antacids (which she is now off) she came home on hills sensitive bland food stuff, but is now back onto chappie.
I and the vet are pretty sure she overloaded on treats, which she never usually has, because we had had a new puppy. I have had to have a good talk with the children about not giving her any treats or feeding her any scraps.
She seems fine, she is all bright eyed and glossy coated but I am worrying to death about her. Everytime she gets up I think she is going to be sick 
Is it quite normal to be a bit fussy when something like this happens? I think i was scared I was going to lose her tbh, we lost a dog year who we had had for 16 years and it was such a wrench so when she became so ill so quickly I thought that was it :( I cried like a baby in the vets, which really didn't help.
She is also due a vaccination tomorrow and vet said it is fine to go ahead with it, but I am worrying that will trigger it again any advice/reassurance greatly received! tell me to pull myself together it's fine, I think i need to be told