My daughter use to work at a local grocery store here (Ralph's) when she was in high school. I remember her telling me of situations like yours, where she not only had to push carts, put when they were short handed, had to work in the deli, the bakery, the flower shop, and later cashier as well. Definitely can be hard work, but it really is good experience. Not only does it keep you hopping, you can also learn different phases of a job, which could lead to future promotions.
Take it easy now and enjoy your evening.
TIS
"Mankind must put an end to war before war puts an end to mankind. War will exist until that distant day when the conscientious objector enjoys the same reputation and prestige that the warrior does today." JFK
Definitely can be hard work, but it really is good experience. Not only does it keep you hopping, you can also learn different phases of a job, which could lead to future promotions. 
