I have Junior District auditions next week (the 30th) and I did a mock audition today. I tend to get really nervous presenting or auditioning but this was on a whole new level. I was physically shaking and unable to calm down even with deep breathing. I played and got through the piece but very poorly and with very bad tone. I don't know what I am afraid or why I am scared. If anyone has any tips about how to calm down that would be great.

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I do know all the music and scales very well so I don't think I'm nervous because I'm unprepared.

Hello,
First off, everyone gets nerves to some degree even after years of experience.
The one most important thing that you should remember is to just go for it, even if you end up making a mistake. Professionals often make a few mistakes in their auditions too. Second, remember to open up your throat and have a lot of air support.
If deep breathing doesn't really help calm your nerves, you can try just taking your mind off of it before your audition or just dive so deep into the music that you can't really think about nerves.
This is all based on my experiences as a performer and auditioner, so some of the information I give might not be correct or apply to you.
Good luck, and happy playing!

Good luck for your future. Please let me know if you need any help from my side.

Useful thread here!