Dog is sick; please help?

[IndieSiren]

My boyfriend's dog (who is about a year old) was perfectly fine in the daytime but he started throwing up water (or watery substance)earlier. He hasn't thrown up since, has no fever, but will not eat now. My boyfriend sais he is lazier than normal too.What could this be? should we be worried? We are going to take him to the vet tomorrow morning. But we are worried.

please help. what should we do for now until the morning?