Interesting thread
For me, I don't think I fit the description of the Impostor Syndrome, which I just read... However, I am highly perfectionnist and have obsessive compulsive tendencies I have to keep in check.
I do hate failing and everytime it happened in my life, I felt like my very core was exposed, so I became highly self-critical, hence the perfectionnist identity I developped over time.
It never got in my way of doing things... I am an overachiever, and what I am anxious about is always what I will work the most on, until it is done and behind me, grinding my teeth out all days and nights in the process... I am a work in progress.
I am highly scared of mistakes... But I chose a career which cannot afford mistakes... So I guess I fit right in now, which made me feel better about myself. My colleagues are the same as me, and anyone who is NOT like that in my field is frowned upon, so I stopped feeling like an outsider to the world, and ended up accepting myself over time...
What helps me is to force myself to be silly with my children, getting right down with them and playing, making animals sounds and just being silly... Being a perfectionist, I have very high levels of anxiety and have a very serious demeanor... So it balances me out to be with children... Also my husband is the complete opposite of me : he procrastinates and he doesn't care how the dishwasher is filled... So I am learning to live with imperfections, and learning that it isn't the end of the world... now, I can even put cauldrons in the dishwasher, imagine that ! I use my husband to balance myself.
So the best advice I can give you is : try your hardest to balance yourself out... Take the seriousness out of failure... Realize that your career is a career and that life is about something else : it is about finding yourself. The less I saw my career has a main quest, the better I felt.
I don't feel like a fraud at work anymore... Work is now a means to live the life I truly love, it that makes sense? But because of my overachieving nature, I am still thriving at work...
Balance.
Sorry if I make it sound easy, it isn't. It is a journey, and a work in progress for me. But going in the opposite direction of who I am seems to help somehow.