How do I overcome work anxiety and impostor syndrome?

I got a new job in a senior position that I don't feel good enough for. I constantly feel like a fraud and am anxious everyday feeling afraid that they will find out and fire me.
Asked by Purple
Hello Purple,  
Thank you for your question. I understand that you are experiencing work anxiety and feel like a fraud every day. You say you fear that others will find out and that you will be fired. This anxiety can be difficult to manage and it can get in the way of your daily functions. I am glad you reached out for support. Many people suffer from work anxiety, but often suffer in silence. Many describe themselves feeling like imposters so the term imposter syndrome has been coined for those that suffer from this type of anxiety (although it is not an official diagnosis). There are some steps you can take to overcome this type of anxiety that may help. I will share those with you. However, it is also important to note that it will be helpful for you to find out the root of your anxiety. In order to find confidence in yourself and your work, exploring the root cause of the anxiety can help you. You will be able to better understand what makes you feel this way, so you can learn to manage those thoughts and feelings that lead to feeling anxious. Some questions you can explore to help you understand what has made you feel anxious are: Where does the anxiety stem from? Are there other things that influence you to feel this way? Anything in particular that has created these feelings for you? Why do you feel like a fraud? 
There are things that may influence you feeling like imposter today. For example, people that grew up in families that placed a lot of emphasis on achievement and had parents that alternated between a lot of praise and criticism, can lead to the fraudulent feelings. Societal or even cultural pressures can also lead to people feeling like imposters. New graduates entering the workforce or those embarking in a new endeavor often experience these feelings too. This is why it is helpful to explore the things that have led to you creating these ideas about yourself.
I encourage you to talk to your mentors. They may be able to help you understand your strengths, growth, and progress to help increase your confidence. Talking to people that know you and your abilities can help boost your morale too. Remember to recognize your expertise. You have a skill set that you carry that it is important to recognize. Focus on those skills and even offer support to others by tutoring or working with younger students. This will help you feel confident about what you know. It's good to turn to others with more experience too, but by helping those with less experience, you can see and hone in on your strengths. It's also important to not chase perfection. No one is perfect so don't strive for that, but rather doing tasks "well enough." Learn to appreciate your work and even reward yourself or celebrate your success. Being able to change your thinking will be instrumental. A lot of what you believe about yourself and your abilities is related to what you say to yourself and what you believe about yourself. Pay attention to your self-talk because that will influence how you think. If your self-talk is negative and pessimistic then you will most likely see your work and efforts in the same way. Having a positive attitude can help you feel secure in what you know and what you can do. If you find that after taking these steps you continue to struggle with anxiety then I recommended you work directly with a therapist to help you better understand the anxiety and the feelings that lead to you feeling this way. A therapist can teach you tools that can help decrease the anxiety and better manage the problems you face due to feeling this way.