Grocery cart pushed into belly 26weeks

Have some soreness after Costco check out person pushed cart into stomach when moving behind desk. Hard to recall exact force or speed but it was a quick sudden bang. Just looking for any reassurance here. OB offered either sonogram early this week or to go to trauma center. She noted it is tough to assess given 26 weeks.

What from here would merit ER other than bleeding? What signs other than bleeding or cramping?