Many (most) bike shops are more oriented towards recreational and racing type bikes, and have a skewed perspective (IMO) about weight, as if it is the end-all, be all. They love to pick the bikes up to see how much they weigh, and are largely influenced by the "OMG! THIS IS SO LIGHT" factor with the high zoot carbon fiber race bikes, that anything over 20 pounds is considered portly. Sorry, just an observation that never fails to make me roll my eyes. It is sort of like going into a porsche dealership with your station wagon and them being surprised that it doesn't handle like a sports car.

I'd say your rig is pretty standard fare - most commuters are oriented towards reliability, some degree of comfort, and utility rather than spec sheet competition.

Unless you are a lighter person, the total weight of bike + rider is only marginally greater on a loaded commuter than the same person on a light bicycle. So I'd say don't sweat it. Besides, if speed is a factor, air resistance is more an issue than weight beyond 16-17 MPH.

Bottom line is that if the bike works for your needs and you enjoy riding it, keep rollin' with a smile on your face.