There are three classes of disaster.  Those you'll survive no matter what you do, those you'll survive if you prepare appropriately, and those that are not survivable.  I focus on avoiding personal disasters (maintaining my car, driving safely, staying out of dangerous places, etc.) and preparing to deal with problems as they arise.
I get a deep sense of satisfaction from updating my car-based FAK, using tonight's example, and it lets me put the need of it out of my mind for the most part.  
In other words, I rarely feel anxiety because I'm ready.
Jeanette_Isabelle, I may be wrong, but I get the idea that your studies may be keeping anxiety-producing thoughts in the forefront.  I don't recommend suppressing those thoughts, but if you are overly focused on them that's not good either.