Since then, I've thought I'd smelled something near my stove, but I couldn't be sure. Last night, I was sure. This morning (even though Jonathan didn't think he could smell anything) I called the gas company and they sent someone over.
The flexihose at the back of the stove needs to be replaced. And he shut off the gas. Now I'm waiting for repairman (eta: 2-5PM). I can't do a thing about Shabbat dinner until he shows up. And until my groceries are delivered, which they haven't been.
ETA: groceries have arrived.
ETA 2: I have to add - the kitchen is very well vented. We keep an exhaust fan running in the window all summer long. Even when the gas company man moved the hose and the leak got larger (and audible) it vented out quickly. So we were not in danger.