That sensation neither loudly announces itself. It sneaks in gently, typically following some things that go not your way. Then comes one error, then another, then a pause when your brain begins to create a narrative around it.
You begin to say things like, perhaps I'm not good at this. Perhaps I can't manage it. Maybe I shouldn't even attempt.
Looking about, you see people moving, developing, solving problems, which causes you to feel even more stagnant. Like you missed something everyone else knew. Like you are falling behind in a manner you cannot repair.
Not because you actually lack the ability to accomplish anything, but rather because you have persuaded yourself that trying will only corroborate your already held dread.
Most of the time, it comes from being overworked, from demanding too much all at once, or from judging oneself too fast against outcomes that take time. Under that sort of pressure, anybody would feel trapped.