Okay, sweating is technically something the body does. Although your mind does not perspire, I’ll bet it feels like it does sometimes. First the big stuff. At its extreme, worry takes the form of a psychological disorder such as generalized anxiety disorder where your life is filled with anxiety about everything.
Another is obsessive-compulsive disorder which is based on fear that you have done or might do something wrong. You feel overcome by worry about what you did and what you are about to do. You keep doing the same things over and over hoping to get it right this time. Being consumed by this disorder allows little time for anything else and leaves you constantly exhausted.
Fortunately most people do not worry to this extent. Even if small matters look large at the moment, in the long run they turn out not to matter very much at all. For those with either of the disorders I just mentioned, self doubt comes close to paralyzing them and makes it difficult for them to quickly decide what to do in almost any situation.
Where does this feeling come from? For many people, it dates back to early childhood when they were given the impression that they were not competent to do much of anything. True, most people are not born prodigies but gradually learn survival skills and go on to develop special talents. Encouragement along the way helps them take their first faltering steps.
Have you ever watched babies learning to walk? The first awkward attempts lead nowhere except landing back on their seats. But with encouragement and support, babies are off and running before you know it.