It is. All of it. In your head. That isn’t to say that it is made up, or doesn’t matter, or is less important, but everything you have to deal with is in how you react to it. Not every crisis is life or death, and if you think through to the end of the issue, it probably won’t result in death or dismemberment, permanent mental disability, or the dissolution of your entire life.
So how do you react to it? Large or small, most issues can be handled with a modicum of calm. I’ve been criticized before for not expressing (or displaying) the appropriate degree of intensity—or distress—that a situation warranted, at least in the opinion of those annoyed with me. My tendency leans more towards the more dire the situation, the calmer I become. This is because I know that crises are more readily solved by a cool temper and a logical, thoughtful response than blind panic, gnashing of teeth, and running around in a tight circle, screaming at the top of one’s lungs while flapping your arms like a chicken. Sure, the latter shows that you are in a crisis, but it does nothing to solve any problem.
And when I act, I act decisively. It’s not always the decision that people want, but it almost always either solves the issue, or at least gets part of it solved.
This applies to everything. I worry about things, yes. The welfare and safety of my loved ones when they are out of range of my immediate protection, the world that my children are going in to, even smaller worries find their way in to my life, but never to the point where I manifest blind panic.
Life is, after all, about how you live it. Don’t waste time panicking over a hypothetical, or doom yourself by accepting a fate forever that you can change. Life is dynamic, and while not everyone will love the changes you implement, do what you must in your life and stop just worrying about it.
"The point of living and of being an optimist, is to be foolish enough to believe the best is yet to come." —Peter Ustinov

Marc, I wish I could be more like you in that respect. It pays to remain calm in situations to be able to think out a strategy to deal with it. I tend to remain calm, but am one of those people whose emotions are all out there for all to see so it is hard. I feel most people could benefit from some calmness during crises. As a nurse I have seen many crises. The adrenaline tendency usually reduces people to emotional wrecks. Can I bottle some calmness and use it as aromatherapy during my work?