Hammy squeaking when breathing

[RossL1231]

Hello guys. I have a Syrian Hamster thats around a 1yr and 6months old. Since about a few days ago my hamster has started squeaking constantly and sometimes sneezing as well i think. I made her a emergency vet appointment as I was so worried about her, They told me at the vets that her lower respiratory was clear and it sounds like an irritated upper respiratory, Which they explained it could be because of the sawdust i use, which i've used all her life. I feel that the vet might have missed something or may be wrong, because it seems very unusual for her to start squeaking all the time. Apart from this she is still active, and is eating and drinking and looks normal as far as i can see, i just hope it isn't anything sinister.

Any advice is much appreciated
Thanks,