Hey Trident,
These forums are here much as you need to get through this.
Anxiety is pretty common. I went through it numerous times and often drank to kill the anxiety before holding sober long enough to see it go away. Keep keeping in mind that a lot of it is simply physical, your brain has been used to considering "drunk" it's normal state, so not-drunk is triggering it to think something's wrong. Such is withdrawal.
But it doesn't last forever; sometimes gets worse after a couple days, but it does go away. I think once it does, you almost look back to think "that wasn't so bad." It's only hard in the moment so give yourself things to do, people to talk to and means to keep encouraging yourself.
You're doing a good thing and you can do it! Once you get past the very initial anxiety phase the good news is: you needn't ever do it again. Ever.