Sickly young dog

[RezDogRendezvous]

He's a year old plott male. Started when he was about five months I'd say. He'll be sick for around two weeks, then off for 2-5 weeks. The older he gets the longer the breaks are between it seems. First symptom is I notice he will stand around humped up and acts stiff when he walks around. Second is two to three days into it, a high fever and loss of appetite. He won't eat, drink or even come out of his house for two or three days. He loses alot of weight each time. Then it seems like it breaks and he'll start eating again lightly. Still acting stiff for about a week. No vomitting and no diarrhea at all. He'll get better and I will just get the weight put back on him and it will happen again. It's currently in effect. He hasn't been sick for at least a month and a half probably this last time. I've had him on some game in between these cycles and he acts really good. I just get him rolling it seems and he gets sick again. It's really annoying and frustrating! He's been to the vet in which they gave me a medication for bacterial infection. I started him on the antibiotic after he was already getting better during one cycle so I'm not sure if it helped or not. I say not, because they said it was as powerful as we could get with him at that time and it should take care of it for good. Help please!!! Thanks!

[Spokerider]

Are vaccinations current and up to date?
Has he been wormed recently?
Did the vet do a blood panel? CBC, electrolytes, liver enzymes and kidney function?

Those are VAGUE symptoms, with the cause being from many possibilities. Start with the labs and maintain an accurate health history on him.