I don't think it ever goes away until you make peace with who you are. Accept that some days you will be less productive than others. Accept that somebody else will always appear to get more done than you.

Give a look at Scott Adams's goals vs systems. Personally, when I stick to my system I am less likely to look to something else to judge if I'm "doing enough" and as a result, imposter syndrome doesn't have a chance to creep in.