It's very easy to be your own worst critic. The phenomenon of feeling like a fraud when you achieve success at work is extremely common, especially among women and minorities. Melinda Gates thinks we should stop feeding into that idea. In a recent article published on LinkedIn, Gates said:
"Maybe people were always surprised to see you were good at math. Maybe the men in your 'weed-out' college courses had guys they knew in the department providing suggestions and reassurance, while you were flying solo. Realizing that the voices in your head are actually messages from a society that’s set up in an unfair way can help you shut those voices down—and inspire you to prove them wrong."
The best thing you can do is to persevere and realize that you're not an imposter and your achievements are merited! Don't give up!