My dog is on a tail of drugs - is she safe?

5 weeks ago I took my dog Rory (Mini Foxy X) to my vet. I advised that she had developed a cough that was like a hack & she had gone off her food. The vet told me it could be an it could be a infection or kennel cough. I was sent home to from the vets with Vibravet & Linctol - Rory then became very sick, lethargic & wouldnt drink or eat. There was still no improvement in the cough either. At the check up i was told that they needed to do a few tests like a chest x-ray & an endoscopy. When I went to pick Rory up she had a chest x-ray, endoscopy, blood test & had been given a anestitic & samples to be sent away. By this stage Rory's weight had dropped to 2.2kilos. I was told take her off the current meds & 5wks later she is on a coacktail which includes cavoloux, bisolven, quartizone which she takes 2's daily. Is this a normal dose of medicine for a dog to be on? the bill is up to a $1000 & I still dont know what is wrong with her. Should I take her to another vet or is this normal?