It's easy to fall victim to the "stress of success." That's what happens when you earn promotions, gain responsibility and wield more authority. Self-doubt creeps in. You begin to feel more fear because more is expected of you—and the stakes are higher if you make mistakes.
Your inner voice can work against you. You may begin to feel like an impostor who does not deserve such success—and your anxiety can translate into an ongoing sense that others will discover that you're ill-equipped in your role as supervisor.