Up coming surgery feeling worried

I can understand your anxiety - I had my double mastectomy in December last year and remember that fear of the unknown. What I can reflect on is that the only way to combat the fear of the unknown is to recognise what you can control and not control. I am going through counselling right now and what I am learning about is that your circle of control is your feelings, thoughts, the present and your actions - nothing else. The future and past is not in your circle of control unfortunately. When you worry - your brain has likely made room for things outside of your control (in the future and past). Because your brain has made room for this worry, the best way to combat this is to fill that space is to replace the space your brain has created with something different in the present. For example, fill it with going for a walk and in the present notice how the leaves move or how the sun feels. Or if you are a tea drinker, put the kettle on and listen to the water bubbling in the jug and consciously make your tea and sit outside with it. It is a scary time, but just breathe and stay in your circle of control. Best of luck!