There is a difference between worry and planning. Worry is the thinking you do when you can’t do anything about a potential problem. Planning is the thinking you do when you’ve done everything you can about a potential issue.
Worry will make you feel bad. Cause all you’ll ever do is beat yourself up over and over again. If it is out of your control, then there is nothing you can do or think about that will make it better, so it just wastes time.
Planning will make you feel prepared. And your planning will get better with experience and time because you’ll come across several situations and connect the dots to similar events. Planning is completely within your control and if you put it on paper or the computer, you “externalize it” and then you be able to think about other things too. As long as you don’t assume and keep an open mind to issues, planning make life a lot easier.