ill dog

Question
We have a 9 month old beagle pup.  Over last 24 hours he has become progressively weak, sore all over, difficulty walking, sleeping excessively, will not eat or drink anything.  He walks with his tail between his legs and back slightly hunched up.  We took him to an emergency vet last night and he tested negative for antifreeze, a stagnant water disease, and lyme disease.  His WBC count was elevated.  He was given Rocephin and subcutaneous fluids and sent home.  This morning he is not any better.  He did go outside and void, but has not eaten or drank anything and is having a hard time moving.  Of note, he is a rabbit dog, and ran for four hours three days ago, but this is normal for him, he runs every other weekend.

Answer
Heidi,
This is a pretty serious problem that is best addressed by your attending veterinarian. He could have gotten a tick bite and has erilichulosis or some other problem, could be neurological.
We have seen too many odd problems like this and they are not possible to even guess at over the internet.

He could just have a metabolic muscle issue from running. I would call the vet if you are not seeing an improvement in the next 24 hours and ask for more answers than what you have explored so far.
Is there a university around you? They see more of these types of problems present and might have a better idea of what could be going on.
That is where I would start if the vet you are seeing isn't giving you the answers you need.