I am so very sorry for the loss of your little budgie. Sometimes this happens to our little ones they hide there illness and sometimes we don't even know when they are sick..
Please don't blame yourself it is not your fault. Seems to me she may of been sick from when you first bought her...
You have a lot of love in your heart to share I hope when you feel better that you will try again with another little budgie to love there are a lot of little budgies out there that need a home and someone to love them... Maybe try a breeder if you would like to try again one day...
Rest in peace little budgie you were very much loved by your mum and sing a beautiful song up high in the sky....
Somewhere over the rainbow way up high
There's a land that I heard of once in a lullaby
Somewhere over the rainbow skies are blue
And the dreams that you dare to dream really do come true
Someday I'll wish upon a star
And wake up where the clouds are far
Where troubles melt like lemon drops
Away above the chimney tops
That's where you'll find me
Somewhere over the rainbow bluebirds fly
Birds fly over the rainbow. Why then, oh, why can't I?
If happy little bluebirds fly
Beyond the rainbow why, oh, why can't I?