Hi. Thanks for your query. Read and understood your history of gastric bypass surgery. You started heaving on Monday before falling asleep. Yesterday you noticed a small that was not peculiar about anything. I would suggest you the following: It is possible thatthesmell of the gastric secretions got into our nose and the memory lingered so that you still are having the feeling of this particular smell continued. Another possibility is that you have developed sinusitis or so casing you to smell the same odor in spite of changing places. I would advise you to get an opinion of an ENT to have a clinical evaluation, examination and further investigations like upper GI endoscopy, Naso-pharyngoscopy and come to a diagnosis and get treated. IF the sensory nervous system has got instigated, nothing much can be done except the aroma therapy. I the cause is found, it can be treated to get a relief.