Preparation is important for a lot of things. When something big is coming, it is human nature to want to be prepared. With some things like a big presentation, it can be a big help to be prepared. With other things like running a marathon, it is necessary to be prepared. A lot of us, regardless of the level of preparation, find reason to worry. We decide that there is a long list of things which can go wrong, and then we allow this to slow us down for some period of time. Worrying is separate from preparation, it is also separate from the actual event. It is something we create in our head, and it leads us to stress and anxiety. Even if we are completely unprepared for something important, it is not mandatory that we worry.
When you find yourself in a cycle of worrying, try to be flat about it. Notice that you are worrying, notice what sensations are happening. Imagine that you are outside yourself, describing what is happening, and describe it to yourself. This gets you into the context. From the context, you likely can have a much less stressful “discussion” with yourself, and instead one which can be productive and positive.
Worrying doesn’t serve you, it is unnecessary and separate from what is really happening. Find ways to move up to the context so you can stop worrying and minimize the stress and anxiety you create for yourself.