Thankyou Sheilarose, and you guessed right I have brain ache!!
He was poorly on saturday afternoon(fine in the morning), high temp, listless, limping on left front leg, then sunday morning the right leg instead, took him to the vets on saturday evening, he had a covenia jab and metacam. Brought him home, he was a little better but had to take him back to the vets on sunday as he was really hot.
We were allowed to bring him home last night, he has been eating and drinking, playfull and cuddly, you wouldn't know he had been poorly.
Vet knew from the rescue lady that he had previously tested positive FIV, then negative on 2nd test.
He decided to do the Glasgow test as a precaution. So today it came back negative. Wait now for other results.
In the last 4 weeks he has had his final vaccinations, been neutered and moved house.
I'm hoping this is all it is thats caused it. He is a very special little lad(as they all are).
Thanks for any advice or knowledge shared.
Nicky x