Labdad is on his way to take Jack to the emergency vet.  They were outside playing catch and swimming.  Came in and while Jack was being dried off, we noticed that he was shivering and his balance was not right.  Got him to lay down.  All legs were mildly trembling.  He was alert, but panting.  After a few minutes, Jack got up, but the right rear leg was unsteady (kinda limping on it).  The left rear still had some trembling.  His balance seemed to be better, but not quite right.
Any ideas on what might be happening?
4pm 7/26/08 UPDATE************
We are back home.  Emergency Vet said it could be heat stroke, a seizure or cardiac problems.  Wanted to keep Jack and run te$t$.  Decided to contact Jack's regular vet on Monday instead of having the Emergency Vet run tests that would keep him overnight.  Rather have him home.
We had been outside for about 45 minutes playing fetch, mostly out of the pool.  Decided he had  had enough and came inside.  Toweled him off a bit and he went to get a drink of water out of the kitchen.  I was talking to wife in the living room when I heard him stumble and looked down.  We have cork floors so at first I thought he just slipped.  He was standing, front right paw in the air the other three on floor.  All four limbs were trembling and he had the ball in his mouth, and was panting.  He dropped the ball and sat down very slowly. I got him laying on his left side. He continued to pant and tremble. His tail was between his legs. and it was like he was paralyzed.  I got the phonebook from the other room to call the emergency vet.  When i returned he had rolled over and his head was up.  After calling the vet I asked him if he was ready to go-fer and he got up immediately, though slowly and his rear legs were still trembling. He was not as fast as he normally is going down the steps, and he put his front paws in the van and hopped up rather than leap into the van.  He got into the driver's seat and would not budge as i got in.  He did sort of a series of reverse sneezes or maybe dry heaves and then sat down in the passenger seat.  by the time we got to the Emergency Vet he was acting normal.
He was happy to be around the nurses.  He tried to sample their lunch and inspect the contents of their trash can.  When the Vet came in he at first went to the vet then got up went to the far side of the island near me and would not budge.  Not like Jack.  Temp was normal.  Lymph nodes slightly swollen, heart sounded OK.  While we waited for the estimate of charges Jack indicated he would rather leave.  This trip only cost $106.00 US.  Had he stayed for the tests it would have been close to $550.00 to start.  Jack had been to the regular vet on Thursday so it seems to make more sense to have the regular vet look at him again than a stranger.
When we got back he asked to go swimming. He was not real thrilled I said no .  More later.  Thanks for the opinions and the prayers.
Sounds maybe like heat stroke? Good idea on taking him to the vet. Please update us or have Andy update us when something is known.
♣ Laura ♣
Good thoughts incoming for Jack... please keep us updated!
Gorsebrook Jackson Triggs, CD, RN, WC, CGN<br />Kelrobin A Twist of Fate<br /><br />
My good thoughts too for Jack.
Update at top
Thanks for the update, Andy. I'd keep him quiet this weekend until you can get him to the vet on Monday.
♣ Laura ♣
Good thoughts for Jack.. hoping he continues to improve
<br /><br />"in moments of joy, all of us wish we possessed a tail we could wag."<br />w.h. auden<br /><br />"This is worse than a divorce... I've lost half of my net worth and I still have my wife"
Prayers and good thoughts for Jack. Please keep us updated, Andy.
Jackie, Champ, and Buddy
Scary!! Please update us Monday. (BTW, I agree with your decision.)
Puff [YF, AKC field line (from competing HT/FT breeder) 62 lbs, dob: 8-'01]
Bess [BF, AKC bench line (from competing show breeder) 55 lbs., 1967-1981] "Poor Bess, the Wonder Dog":