Oh yes! This is very common, especially to people who are sensitive. Remember, most new age shops have many various crystals in them--their energies swirling all around and then, add to that the mix of various people coming and going and the other items in there with energy....it can at times be very draining.
When I read in a new age shop, there would be times that I'd leave work (I worked an average of 5 - 6 hours only) and be really wiped out. I always made sure I had water to drink, food to eat in between my readings, but still I could leave there either incredibly happy and filled with excess energy or be as you mentioned, feeling like I was filled with lead and dragging myself home again. Of course, I'm also an empath, and so I tend to soak up the energies of others too.
I sometimes get this way even at a regular store--the grocery store is a really bad place for me--I always leave there and feel like I need a nap and I get headaches easily from the grocery store. Doesn't matter if I'm in there 15 minutes or an hour. I am also drained when I go to the clinic for my allergy shot each week. I do my best to find the quietest corner in the clinic, often far away from everyone else, so I am not drained afterwards. Once I get my shot and can leave- I hurry home, and find I need to make myself a snack again (though I usually have JUST finished eating breakfast before the appointment), and sit and relax for awhile--often w/o any television or music on. I need the solitude and quiet.
Any store/area with much activity or a lot of people around - can be draining. So, definitely take caution to ground yourself now--especially going into a store with crystals and such.
I would recommend you grounding and protecting yourself before going into any crowded store/area.
Even at times just being around one person can do this to me. The ones I refer to as the psychic vampires.
