Weight restrictions?

So I go to the doctor on the 18th, but I'm wondering if I need to stop lifting or moving things. Since I've gotten pregnant I've been really careful about not lifting any of the kids in my room (I'm a Toddler teacher in a childcare center) and I've had previous losses so I want to be careful this time. However every once in awhile I lift them up and snuggle them, but I feel a pulling across the top of my stomach, and then if I go to like nudge something heavy or move just right I feel a pulling down in my groin. I'm trying to be careful, but is this normal? Should I be concerned and not do anything?