As, I have mentioned on your other post, I'm so sorry for your loss...it is never good whether they pass suddenly, or after an illness, but it is such a shock when they pass quickly...we lost our little Arya (the yellow budgie in my profile pic) four days after coming to be with us...she showed no signs of illness when she went to sleep and was found on the cage floor in the early morning. I hope you and your family, as aluz et al. mentioned, "you may consider getting another budgie friend to brighten your days."
I never for a day gave up listening to the songs of our birds, or watching their peculiar habits, or delineating them in the best way I could.
John James Audubon