Question

We have a four month old Yorkie puppy.

Last night he got us up three times; unusual for him and did not want to go back to sleep.
As we keep him in a small carrying case, but bring him to bed in the AM with my wife and the other two dogs, we thought that that's whathe wanted as he barked, whined and cried after the last visit outside at about 3:00 AM. He was very lively and wanted to play with the other two at that time.
When he got up this AM, he was soaked aon his legs and belly and had peed in the carrying case.
Once outside he had trouble walking.
We bathed him and kept him wrapped and warm.
He seems to be drooling constantly (He has also been sneezing for the past three to five days, and did at the last "out" last night).
He is very tired, lethargic and without his normal 'bounce".
I tried him walking after he dried out from his bath and he was unstable and actually walked into a chair.
He is drinking.
His nose is cool and wet.
Yesterday, in a walk in the park, he drank from a pond and stream.
What is going on?