Breathing too fast???

We have a 4 month old 6,9lbs Mainecoon kitten and noticed he was breathing at 35-40 breathe per minute. The Vet told us that it is twice as fast as normal anit could indicate something else (asthma, Cardiac disfunction). During the first two weeks when he got home, he was sneezing a lot but is OK now. He also vomit twice during the first 2 weeks but we think it's because he eat something bad (he eats everything he finds: Dust, piece of paper, littel grain...anything).

He also have very smooth poo but for that one we think it is the new food we bought because one of our other cat also has the same symptom. The Vet said it could also be worms but since he was treated against it twice the possiblity are remote. Nevertheless we will proceed with a third treatment to be on the safe side.

Other than that he plays a lot, run all the time and seem perfectly right

is the Vet over cautious, trying to make money with me or what?