Follow-up budgie question

Question
Thank you!  I went with a younger-looking bird from a pet shop.  My next question has nothing to do with age, but it is something that I'm very concerned with.
I brought my budgie home last night and put it in the cage.  The bird ended up at the back of the cage as high up as possible.  It spent the entire night there, and I don't think it slept at all.  This morning, I changed it's water and the poor thing had a scare and ended up at the bottom of the cage, which is where it still was when I left for work this morning.  It hasn't eaten anything, it hasn't touched its water, and it is breathing very rapidly.  Is this something that will pass once it gets more comfortable with the cage?  I'm just so worried that it's going to starve itself.  Is there something I can do to make my bird more comfortable?  Can I do anything so it will eat?  Thanks for your help!
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The text above is a follow-up to ...

-----Question-----
I'm looking into getting a budgie.  Some sources say that I should not get a budgie over a few months old, because they won't tame.  Other sources say that older birds can be tamed over time as long as you're extremely patient.  Can I get a bird that's close to a year old and still be able to tame it?
-----Answer-----
Hi Roni,

It is alot harder to tame an older budgie,it requires alot of patience! And there is no guarantee that he/she will become tame,I would recommend getting a younger bird but if you are willing and able to put in the time to try and tame an older bird then go for it.
If you do choose an older bird I would try and get one from a pet shop or a bird that hasn't been kept in an aviary,it sounds cruel,but a bird who hasn't been kept in an aviary will be easier to tame as it isn't accustomed to flying and interacting with other birds,making it a little easier for you to tame him/her

Answer
Hi again Roni,

I'm glad you went witha younger bird :) Sounds like your bird is a bit stressed get it some sulfur aid from the pet store this helps with stress. Try offereing it stuff like millet spray fresh grass (weeds) this should hopefully entice it to eat.
Once your bird calms down and gets more used to it's new surroundings it will eat and drink normally. If it is really stressing ie flying around the cage rapid breathing etc cover the cage with a towel or put your budgie in a dark quiet room.
It will thake the bird about 10-14 days to be truly comfortable in it's new surroundings.