I only know of the 5 - 4 - 3 - 2 - 1 technique.

I like to hold in a deep breath for 7 or so seconds (as long as I can), then release. It sounds scary to not breathe, I know. But from a physiological standpoint, lowering your heart rate makes you feel closer to “normal” as opposed to being anxious. The quickest way to lower your heart rate in a time of distress is to force it to circulate less oxygen. This has been the most helpful to me!

One of the best bits of advice I've been given in that regard is to describe everything I see, hear, feel, taste, and smell in extreme detail (texture, color, similarities, irregularities, as many attributes as you can think of for each sense). It gives you something concrete to focus on and process, hopefully allowing you to get your mind off of the anxiety inducing scenario long enough to calm down a bit.

Also it's good to identify the kinds of things that stress you out and then ask yourself questions about them (how likely is worst case scenario? Is worst case scenario really that bad or just an inconvenience? What can I do about this? Anything to analyze/rationalize the situation).

I’m having gallbladder surgery this Thursday and my anxiety is so bad right now. I’m afraid I won’t wake up, any help would be appreciated 😥