@Ot2010 I'm sorry anxiety is making you feel this way. I've been there in the past and it's really tough. It controlled my life, still does sometimes. I used to get incredibly anxious before a holiday, but tended to be ok once I got there. Hopefully the same for you!
A few things I use from CBT which might help (sorry if you know all this but these are the quick wins I remember in the moment which helps)
Is the worry real or hypothetical? ( Google the worry tree). If it's hypothetical, challenge your thoughts and tell it so. It's making up what could happen, it's not worth your energy (and overthinking is draining so one less worry is fab). If it's real, can I fix it quickly, yes, then fix it. If no, park it until later and allocate some time to worry/ fix it.
Breathing - in for 4 through your nose, out for 6 from your mouth. Very grounding. Think about your body too, what feels tense, are you hot/cold, what does the seat/bed feel like, unclench your jaw, drop your shoulders.
Or the breathing square is good if you're panicked. Find a square - TV, window. Breathe in for the top, hold for the side, out for the bottom, hold for the side, repeat.
These are the things I can do when my anxiety is really bad as they're quick wins and simple.
I hope you get to enjoy your holiday, you deserve a break :)