This moment right now is not so bad.
If you're sitting somewhere, reading this, wherever you are, whenever you are, it's not so bad around you.
Sure, somewhere in the world there are people facing very tough challenges. But they are less worried about their predicament than you are right now. When you are in the midst of the battle, you don't have time to worry. You just do what you have with the resources on hand.
Right now, on the other hand, you are probably idle. You have time to sit, and read. Read things like this essay. You have time to worry.
And in that time, you feel something inside, some unique mixture of anxiety, stress, and worry.
But every thing that you're worried about is not happening right now. Right now, you're in a relatively safe place. You have food to get through the day. You're warm enough. Nobody is physically threatening you.
Seneca, Letter 5:
Beasts avoid the dangers which they see, and when they have escaped them are free from care; but we men torment ourselves over that which is to come as well as over that which is past. Many of our blessings bring bane to us; for memory recalls the tortures of fear, while foresight anticipates them. The present alone can make no man wretched.
All the worry is in your mind. Everything bothering you is either in the past or the future. Either rehashing past mistakes that you still don't understand, or fearing future crises that you have been convinced are coming to pass.
If you pay attention to the moment you're in, it doesn't contain any of those things, past or present, that make you feel threatened.
So set them aside, write them down, come up with a plan to address each one. But stop fearing them. You're in no immediate danger. The feeling that danger is right here and right now, and the anxiety that produces is your brain's urge to do something. The only way to resolve it is to do something. Decide what to do and then do it.
If the worst does come, the person who faces it will be you, armed with all your logic and reason and resources. (Meditations 7-8) The person reading this today is naive and uninformed compared to the person that will face the future crisis when and if it comes. So shore up your reserves, keep your options open, and trust that whatever crisis, foreseen or unforeseen, if it comes you'll face it head on.
When that happens, you won't have time for worry. You can't both act and worry at the same time. So if you are worrying, you are not acting.
Stop worrying. Start acting.