German Shorthair shortbreath

[charlie]

I have a german shorthair. He is now about ten years old. Lateley he hasnot been eating, and drinking less. When he is laying down I notice his breath is short and quick in and out, then his body quivers a few times then another short breath. The last couple days he hasn't eaten hardly anything. The last time I took him to the Veterinarian they did x-rays and said all is well. Then the blood work showed high calcium, and they couldn't figure anything out. They gave me 1 week woth of Ampicillin, and 3 days Azium? This was about two weeks ago and he gained a little weight and now back to the same thing, but the breathing thing is still there. He started refusing to eat tuesday, and Wed I got him to eat a couple beef hotdogs. Any help would be greatly appreciated!