Hello. This morning I came home from work and my jack russell was sleeping with my wife like usual. When I came in the room I put him on the floor to go outside and use the bathroom but he just sat back down. When I would walk and call him to me he would stand but seem wobbly and stick a back leg in the air and sit back down. Now he is shivering like he is cold and won't get up to walk. I took him outside to go to the bathroom and he did so I picked up a stick to see if he would go after it like he usually does. He did run after but his back legs seem to kick funny and he wouldn't jump on the step when I tried to get him back in. When I carried him back in he walked long enough to get to the living room and has been laying down since. He is 3 yrs old and the first I've ever seen of this and I was just wondering if anyone might know what is going on?

Could be several things. Best thing is to get him to the vet.

His feet are probably cold. But, just to be safe, see a vet.