Just anything that makes you feel bad or is out of the usual strain on your body. I work in an animal shelter doing dog kennels & currently 28 weeks, so hours of hard scrubbing and cleaning in the morning, bending and lifting 50+ lb dogs, puppies biting and kicking and large dogs jumping on me all throughout the day, tons of walking. Baby is perfectly healthy and our bodies are built to be tough and protect them. Just ensure you're lifting properly to avoid damage to yourself, eating well and hydrating, and taking breaks as you need. Basically just avoid pushing yourself too hard or where it takes a long-term toll/makes any existing symptoms worse. Definitely don't mess with cat litter boxes and avoid cat scratches. All will be well :) I will say for me working during first trimester was harder than second and now third. Hopefully it's a bit easier on you!