Ate only a sandwich for lunch & hour later abdomen distension & felt very weak. Saw pcp but vitals ok & no sonogram 'til mon. When should I go to er?

Well. If intractable vomiting with dehydration or fever. Food poisoning usually hits in 6 -12 hours after eating. It likely ok, are u pregnant? Why the ultrasound?
Wow. So are you pregnant? A sonogram for what? Are you looking for a the sandwich? Take a laxative and stop eating bread. Roll the inside of the sandwich in a lettuce leaf; much better for you. Drink more fluid and stop worrying!