Sick puppy?

I think Zeus is a bit under the weather. He ate breakfast like normal, but he's not his usual (very) bouncy self. And dh said he was very slobbery last night, although I haven't seen any of it today.

He had his second set of shots on Friday. Think it could be because of that? I know my kids are someetimes a bit off after shots, but I don't know if it's the same with dogs.

Any reassurances would be welcome! Zeus is about 1 and recovering from demodex, so I'm always a bit worried about him.