Molly did not show signs of being pregnant till she was about 5 to 6 weeks. But It depends on her size. Molly is 7-8 lbs. I had a tiny yorkie 3lbs show at 4 weeks. Also that canned food could have caused gas. Which since she is pregnant I would ask the vet which med. for that. I would wait and see how she is in a few hours before you make that long trip.Hope your yorkie will be okay.Blondschilli