I don't have the severe anxiety that you experience, sweetie, but I do get a ramping up while in the tube.
When I feel the waves of anxiety coming, I begin to count my breaths up to 10. If the anxiety makes me forget what number I'm on, I have to start over. It's a mind trick a spritual teacher taught us to get out of the jabbering mind and into a peaceful state.
If that doesn't work, I start praying like crazy...and it helps...I know I'm not alone with it, at least.
But just don't put that thing over my face until my eyes are closed!! I don't wanna see nothin'!

Take care of yourself, dear. And no caffeine that morning...