Hi @Emgod, welcome to the forum. Sorry to hear what is going on at the moment with your anxiety. I was diagnoses with a serious health condition 2 years ago and had similar anxieties. I required an MRI scan as part of the initial diagnosis, and woke up about a week before with what I can only assume was a severe panic attack... the first time in my life I had had anything like that. I woke up knowing this scan was coming and I had to pull the covers off myself as I felt like they were closing in on me. I even had to turn on the light as the darkness felt the same. I couldn't get back to sleep until the sun came up. I had the light on and did puzzles on my photo to distract my mind.
One thing I would strongly advise, is don't google anything to do with your treatment. You will work yourself into a panic with so many potential possibilities to worry about. If there are things you need to find out, research very carefully, dont get too far ahead, and speak to a nurse or someone similar if you can to get your questions answered.
For me, the main thing that kept me... less panicked... was to only focus on what was next, whether it was another procedure or scan, or test result. Keep reminding myself to wait for that, focus on that, then when that happened, focus on the next thing. Thinking about that 'what ifs' and 'maybes' will work you down into an anxiety spiral. Just focus on what you know and what is next. That's usually enough to worry about without adding a bunch of hypotheticals to it!
If you can't stop worrying about what may happen, and that can very difficult at times, then try to think about what would you do if it did happen. i.e., your medical team with deal with it, you've come this far, you can deal with a bit more, your doctors know what to do, there's plenty of treatment option for so much these days... all these thoughts will help to rationalise these thoughts and remind you that even if something bad does happen, it's not the end of the world just yet, and that you can get through it. Speaking to a nurse or someone to go through your options should you need them helped me a lot as well.
I hope you are recovering well from your surgery, and that you can get some peace from the anxiety and panic attacks.