I've been a professional software developer for almost 10 years, and I _know_ I'm competent (and not an impostor) as demonstrated by my current position and ability to ship things.
However, lately after viewing developer blogs I become overwhelmed that I actually don't know enough and am not a "real" developer. I seem to have formed a notion of an ideal developer in my head and I compare myself against this imagined construct which leads to these feelings. I admire how these people have so much deep knowledge and can express themselves so clearly and concisely, then wonder why I am not like that.
I barely have the energy after work after taking care of my family to do anything further, and I know programming isn't everything but I do have a desire to learn more and improve myself.
I recognize this isn't healthy nor is it rational, but it's just a feeling I can't shake lately.