..and if a dog is so ill .. then it may well just die  anyhow  
I have owned dogs for 50 yrs, worked at a Vets for many years ...  and have seen more vomiting/diarrhoea  than I want to remember  ! There are many many causes - from very serious infections, to blockages, to other ilnesses in other organs , to parasites, to eating/drinking stuff ..and there is NO way anyone can tell , unless  they are trained, and can see /touch the dog. 
You are doing the right thing. Late, yes.. but the right thing . 
 
I definatly will take him to vet frist thing tomorrow morning.