What can cause these current symptoms, heightened sense of smell, nausea, vomiting, fatigue, and mood swings. I had a complete hysterectomy in 2012.

Migraine Headaches. Heightened sense of smell may be descriptive for something we call "osmophobia" while the other symptoms are commonly known to be characteristic of migraine headaches: nausea, vomiting, fatigue, and mood swings (irritability). Of course, you never said you had headaches but there is also such a thing called "acephalgic migraine" which is a headache-less migraine....Symptoms of aura only...Maybe?