She will probably know that she is slowly dying - and therefore, sadly, she will be suffering. There is no chance of
disease cannot be cured, though in the early stages
, it can be controlled and slowed down), so the longer you leave things the worse she will get. The smell you talk about is probably her breath - and the smell is from the toxins building up inside her body.
I hope you can muster enough strength to take her to the vet, as you have suggested, tomorrow morning.