I’m a grown-ass woman and I’m afraid of my boss.

Fear at work does not mean you are weak, junior or bad at your job. Sometimes it means your nervous system has learned that one person is unpredictable.
You can manage complex investigations, advise senior leaders and make decisions with serious consequences. Then your stomach drops when one name appears on your screen.
That contradiction is more common than we admit. Professional competence does not make us immune to power, unpredictability or the slow erosion of confidence. When expectations keep moving, feedback feels personal or every decision is second-guessed, even experienced people can begin to work from fear.
Notice what is actually happening
Separate a demanding role from a damaging pattern. Are expectations clear? Can you disagree safely? Does feedback help you improve, or leave you afraid to make the next decision? Do you spend more energy anticipating someone’s mood than doing your work?
Write down specific events, dates and effects. Not to build a dramatic case in your head, but to replace the fog of anxiety with facts. Patterns are easier to evaluate when they are visible.
Get your perspective back
Fear makes the difficult person feel like the only person whose opinion counts. Speak to someone grounded: a trusted mentor, former manager, colleague, coach or employee-support service. Ask what they observe, not simply whether they agree with you.
You may decide to clarify expectations, ask for written priorities, seek support, raise a concern or leave. None of those choices makes you a failure. The goal is not to prove that you can tolerate anything. It is to do good work without disappearing inside someone else’s behaviour.