Hi,
I’m sorry about your little budgie, and your experience at the emergency clinic. Most of those clinics do not have a vet who knows how to treat birds. Unfortunately your bird most likely has been sick for at least a few days, and was just acting OK. They hide signs of illness until they are really sick. Many owners miss the early signs which can be a change in droppings and appetite. Other changes of daily habits can be a sign of something wrong. There is nothing we can do because we are not a veterinary service. Symptoms alone cannot diagnose what is wrong. The Vet must do testing to determine what might help the bird. Hopefully you were able to find an Avian Vet today, as that is the only way to help your little bird.
Take care,
Brenda