I think you need to elaborate on this a lot in order to get relevant feedback. Speaking from experience, a lot of the answers you're getting here won't work for someone who's started a family—you need to be very precise in identifying and targeting the root cause, and you don't have tons of free time for side projects and after-work learning.
In what aspects of your work have you felt out of your depth? Is this sense in comparison to others around you, or to the work itself? When do you most often feel it?
How long have you been in your current company? Are you losing interest in your job, or in web development, or in computers in general?
What you need to do will depend a lot on how you answer questions like these. It honestly might be as simple as getting a new job that stretches and engages you more than your current one.