Hi and welcome to YT
!
The good news is that Cushings is very treatable. My Wylie has had Atypical Cushings since he was about 4 or 5, so very young! He is now almost 10 and you'd never ever know that he has it bc he is super athletic, a wild man, and doesn't show any major symptoms except for recurrent skin issues (even when cortisol is controlled).
It can take a long time to titrate Cushings meds, but once you have her on the correct med and it's titrated, you will see many of her symptoms resolve since the cortisol is no longer running rampant. So, it's really important to start meds asap. They are not the greatest of meds, they're quite toxic - but most dogs do so well on them - Wylie has never shown a side effect to the meds.
Hang in there and just know that Cushings, while serious, isn't a death sentence and that dogs can live very well with the disease.