Chivalrous or Sexist?

Many of you know that Brian has Muscular Dystrophy so I do all of the heavy lifting at our house. I am used to it and it doesn't bother me at all. (Daddy didn't raise no weakling!) I went to Home Depot today because I needed 8 cubic feet of sand or 700 lbs. I loaded the bags onto a cart and, because I had the kids with me, I pulled the sand with one hand and pushed another cart with the kids in it with the other hand. When I got to the cash register, the guy looked at me and said, "Did you load all that by yourself?" I of course told him that I did. After I paid for it, he insisted that I couldn't load it into my car. (Little did he know that I had already loaded 100 lbs of fertilizer and several hundred pounds of compost and soil into and out of my car.) So he tries to move the cart and he can't even budge it! So I started pushing the one cart and pulling the other out to my car. He of course calls for some other guy to come out and do it for me. It was nice to have the help don't get me wrong, but it is kind of rude to assume I can't lift that kind of weight. I am all for guys being guys and girls being girls. I just hate the stereotype that "my husband should be doing that work." If we all sit around and wait for our husbands to do everything, we would get nothing done!