I’ve never heard of imposter syndrome. But now I’m aware of something else I suffer from. I’m going into my 6th month on medium and I too feel exactly as you.
I see writers wanting to earn $100, I’ve earned 35x that. I see writers wanting 100 followers, I’ve gained 1100. I’m approaching 100k views but it’s never enough and I doubt myself.
I question my purpose for writing any more. I guess I say something people relate to, it’s in my stats. But my insecurities wreak havoc on me emotionally.