I find breathing exercises very helpful in those types of situations, especially the waiting room.
If interested, you could google: breathing exercises stress reduction
or something similar, and find some you could use without anyone else noticing. Some of the are very quiet and very calming.
I am sure others will be along to comment, too!
Best wishes for your appts. I am sure you will do just fine!
It's always good to hear from you!

WC