The root cause of a worrying is lack of clarity on what to do next.
If you want to stop worrying about the future, then figure out what it is that is keeping you worried, and then ask yourself - what can you do about?
Either you are going to have an answer, and then you won't have a reason to worry because you'll know exactly what to do net, or if the answer is that you cannot do anything, then just stop worrying about it.
1) Worrying about something so far out that it might not happen.
The way to stop worrying about future problems is to get more information to understand the problem, and to figure out the next step.
2) Being nervous about the things outside of your control.
As stated, they are outside of your control so there is nothing you can do; the only sensible solution is to stop worrying about them.
3) Worrying about something that you know you need to do, but you also do not want to do, like laying people off, for example.
This is perhaps the most challenging worry as it involves emotions, and emotions are not easily quantified.
To stop worrying about this type of problem, put the emotions aside and think through the logic of the business case first, quantify the business issues. Once you understand why you have to resolve the issue at hand, you will find a way to deal with the emotions of doing it.
Even after gathering information and most-likely knowing what to do, you might still feeling lacking in knowledge to get it done.
The hack to getting the confidence to do a hard thing is to remember a time when you did something just as hard.
The muscle memory of knowing that over a long-enough time you can do hard things, even if some work and some fail, will give you the confidence to make a call and move forward with every new hard thing that you encounter.