Cramping in 2nd Trimester

I am finding that after doing any relatively “strenuous” activity—grocery shopping trip, cleaning, doing laundry, making the bed, etc.—I am experiencing cramping/aches/soreness in my uterus. I am 16 weeks & 3 days. Is this something I should be worried about? I’m not doing anything more difficult than I would usually do, no heavy lifting, not even breaking a sweat during these activities.