I have a 5month old puppy on Tuesday he's started vomiting his food up then later it turned into a white fomy stuff. He tried eating yesterday but shortly after it came back up, this morning he drank a little work and it came up. He hasn't been able to eat or drink for 2 days please tell me what could be wrong?

We don't know what shots he's had, and what he's been exposed to, and so on... so you need to get him to a vet TODAY. Not being able to drink is especially serious.

He needs to be seen by a vet. There's absolutely no way for anyone to diagnose online. In order to find out what's going on with your puppy you will need to take him to the vet. That's the only option. You really won't find answers on your computer.