my budgie has pneumonia help please???

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my budgie is just over 5 years old never been ill. He has always been an active lively bird i have taught him a range of tricks and phrases which normal he would sit talking. However recently i noticed he was sitting more fluffed up and less playfull and struggling to fly more, he has never been strong at flying, but he was more out of breath. Then he was remaining fluffed up panting in his cage. So immediately i took him to the vet, which was on Wednesday, who said he had pneumonia and gave me antibiotic to give him through a syringe and as he is very hand tame with me it is quite easy for me to do. However the vet said if i didn't see improvements whithin 48hrs to bring him back and have him put down, i thought he improved however today he seems quite lethargic again :( i don't want to take him to the vet as he is not a specialist and seemed more concerned with going home than treating my budgie. I was wondering if anyone could help? and if anyone knew of an avian vet in Staffordshire iv looked but cannot find one at all.
thanks to all
sarah x