This is a bit of a trap, because it kind of breeds anxiety.

Most people who are worried are aware that logically, it is unhelpful. You can phrase it however you like but if someone could stop worrying, they would.

Human's are hard wired to "worry" about threats. It's how your ancestors avoided being eaten by a sabre toothed tiger long enough to be someone's ancestor. Worry is in our nature.

As you accrue things you're not worrying about, and as you don't worry about them over time, it can create extraordinary tension which in my case and many others presents as anxiety - an overwhelming and unreasonable response to a threat.

So for loads of people, trying not to worry kinda works until it doesn't.

There's loads of healthier ways to manage worry and anxiety, that I won't try to summarise here, but ACT and CBT are good places to start.

Essentially what you said, but I'd like to phrase it the way a counselor said it to me when I was under a lot of stress at work. Stress is the gap between our expectation and reality. Say you expect to be/produce/achieve/whatever 100%, but you are only capable of achieving 80%. The stress you experience is that 20% gap. Change your expectations to meet your reality and that stress will be resolved.

Now, it may still be that others might still want or expect that 20% from you, but that's their problem and their stress. If you cannot produce it anyway (which created your stress in the first place), existing in the stress-gap clearly won't make you able to do it anyway.

This is essentially the Serenity prayer as used in 12-step programs:

God grant me the serenity to accept the things I cannot change, Courage to change the things I can, and Wisdom to know the difference.