I assure you, your dog is not not eating because it remembers being sick. She probably doesn't remember what happened 15 minutes ago. She might not be eating because she's nauseated or worst case scenario she has an obstruction from eating something she shouldn't have. Just FYI--by offering her something different (the cheerios or the chicken, even), you're giving her the option to be a picky eater. A dog that won't eat always really frightens me. I would see your vet ASAP.